Early days in ABAP
Hi all,
Lets try and recollect our very early days in ABAP,when we were learning just the basics.I am sure most will have a memorable incidents of the days.To start with mine i can tell while learning the ABAP for very first time i used to be so much confused with the data declarations,why do we used structures,table type and what was the difference between them,difference with with header line and without it..also why do we need to need to maintain text modules when we can directly text boxes in forms...and a lot more. Now when i have the answers to them with experience the questions seemed so silly..:)
Hoping to hear more silly incidents of our past.
Thanks,
Abhishek
Hi,
If your calculating dates please do not manually calculate it like that.
You need to determine like week numbers, month and days.
The best way to do it is by using FM related to dates. Play around with these FMs in your program:
Function Modules related to Date and Time Calculations
CALCULATE_DATE - Calculates the future date based on the input .
DATE_TO_DAY - Returns the Day for the entered date.
DATE_COMPUTE_DAY - Returns weekday for a date
DATE_GET_WEEK - Returns week for a date
RP_CALC_DATE_IN_INTERVAL - Add days / months to a date
DAY_ATTRIBUTES_GET - Returns attributes for a range of dates specified
MONTHS_BETWEEN_TWO_DATES - To get the number of months between the two dates.
END_OF_MONTH_DETERMINE_2 - Determines the End of a Month.
HR_HK_DIFF_BT_2_DATES -Find the difference between two dates in years, months and days.
FIMA_DAYS_AND_MONTHS_AND_YEARS - Find the difference between two dates in years, months and days.
WEEK_GET_FIRST_DAY - Get the first day of the week
SD_CALC_DURATION_FROM_DATETIME - Find the difference between two date/time and report the difference in hours
L_MC_TIME_DIFFERENCE - Find the time difference between two date/time
HR_99S_INTERVAL_BETWEEN_DATES - Difference between two dates in days, weeks, months
LAST_DAY_OF_MONTHS - Returns the last day of the month
DATE_CHECK_PLAUSIBILITY - Check for the invalid date.
DATE_2D_TO_4D_CONVERSION - Year entry: 2-character to 4-character.
DAY_IN_WEEK - Input date and will give the name of the day 1-monday,2-Tuesday....
SD_DATETIME_DIFFERENCE - Give the difference in Days and Time for 2 dates
Similar Messages
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Anyhow, I rang them today and they said that my PlayBook was still at the Harvey Normans Office waiting for BlackBerry to come and pick it up (so much for the week to a week and a half)!! The other thing that the Harvey Normans lady said today was that repairs can be up to 4 weeks (well this is NOT what I was told when me and my girlfriend took it in to get sent away for repairs)!!
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Boxy7I'm guessing the retailer forgot to call straight away - my PlayBook repair was swift when I dealt directly with RIM.
1. If any post helps you please click the below the post(s) that helped you.
2. Please resolve your thread by marking the post "Solution?" which solved it for you! -
I am shocked, stunned and amazed! ................(and delighted)
I know its real early days... but at about this time after CS4 was made available to install...this forum was flooded with CS4 issues and they went on for sometime. (Including my own rants)
I think Adobe has been very clever and the MPE / CUDA / NVIDIA smokescreen has worked.
(just joking but I do note the considerable amount of discussion about hardware / performance ie cards / HDDs... and nothing about software ie CS5).
As has become norm on this forum..the big continuing issue is AVCHD. (boring, boring, yawn,)
Jeez...surely someone is having a great editing experience with this crap. If so...can they let the other guys know and then tell them how to do it
Actually I suspect this CS version is really a great release and will be installing it myself tomorrow from my download. to a new machine (Have been waiting on new Ram due to 1st batch being problematical).
Tempting fate but I expect no issues at all and I wil be able to put the CS5 suite into productivity/earning mode far earlier than I expected.function(){return A.apply(null,[this].concat($A(arguments)))}
trying to cram everything into the archaic 32 bit memory space
Oh, soon we will say that about 64 bit as well.
Let me start in another end. What kind of computers were used to put the first man on the moon?
Well, if the development should have increased as much as the memory space has, we should now be able to travel in time by the use of a modern computer.
64 bit will not give better stability, you see, people are the same (people = computer owners) and they will of "good old habit" screw up their computers by installing whatever, clicking OK/YES too many times, and so on. When did people get the opportunity to do so? When the memory space got big enough for making GUI "for everybody".
Dag -
Very Early Days, 2mbps - Billion 7800n and SnR Twe...
Hi there,
Broadband's only been activated 2 days ago, and whilst I cannot run BT's speedtest.net for some reason, I have these stats from the router, plus I am running the Billion SNR tweak lowering SnR margin by 4.5db...
Upstream
448
Downstream
8128
SNR Margin(Upstream)
18.0
SNR Margin(Downstream)
4.1
Line Attenuation(Upstream)
24.0
Line Attenuation(Downstream)
42.0
Is it a bit premature to be messing around with the tweak settings with the figures I have...? Should I just let thinks settle for 2 weeks or more?
Currently I have 2 Mbps down and 0.36 up...
Thanks..you should really leave everything alone for the first 10 days including using the home hub so that if any help is needed after that period we can help you further
If you want to say thanks for a helpful answer,please click on the Ratings star on the left-hand side If the reply answers your question then please mark as ’Mark as Accepted Solution’ -
Absence days caliculation based on working days HR ABAP
Hi experts,
I am developing one report that is for Variable Bonus report. We are evaluating the data based on the Variable Bonus period based on Selection-screen. for ex: 01.04.2007 to 31.03.2008
There is one record in the IT2001 with begin date 26.01.2008 end date 25.07.2008 for the absence type 0620(Unpaid leave). But our Variable Bonus period is 01.04.2007 to 31.03.2008. I want to calculate absence days for the above record from 26.01.2008 to 01.04.2008 and 26.01.2008 to 31.03.2008
Please let me know any function module which gives me exact absence days.
i have tried RKE_SELECT_FACTDAYS_FOR_PERIOD... but its giving based on factory id but in my requirement the working days differ from each employee ...for ex: 5 working days in a week or 5.5 working days in a week, 6 working days in a week ....for each employee....
Please suggest me what could be done to achieve this.....
<REMOVED BY MODERATOR>
Thanks in advance....
Sreenivasa Sarma K.
Edited by: Alvaro Tejada Galindo on Apr 9, 2008 6:02 PMHi sudheer,
Thanks for your reply.
Yes i need to caliculate the absence days based on S_vbpd(vb period from selection screen). but here in IT2001 Absence day are maintained as contract period ... for example..
vb period 01.04.2007 to 31.03.2008
start date end date
25.03.2007 03.04.2007
20.03.2008 05.04.2008
01042007 31.03.2008
___________|___________________________________|_____
25032007 03042007 20.03.2008 05.04.2008
But system caliculating absence days for period 25.03.2007 to 03.04.2007 and 20.03.2008 to 05.04.2008 in infotype IT2001 total but i need absences from VB period start date and contract enddate(01.04.2007 to 03042007) next period (20.03.2008 to 31.03.2008).
Please help me for the above scenario.....i hope i made it clear my requirement...
Regards,
Sreenivasa sarma k. -
How to calculate number of days in ABAP?
Hi,
I have a condition as below:
If (field1 - field2) > 12 Months
E.g field1 = 31.05.2011 & field2 = 10.11.2011
Can SAP actually minus dates and check if the difference is greater than 12 months?
How do I perform this calculation?
Pls advice.
Thanks!
Moderator message : Date FAQ, duplicate post. Thread locked.
Edited by: Vinod Kumar on Mar 2, 2012 1:50 PMHi,
If your calculating dates please do not manually calculate it like that.
You need to determine like week numbers, month and days.
The best way to do it is by using FM related to dates. Play around with these FMs in your program:
Function Modules related to Date and Time Calculations
CALCULATE_DATE - Calculates the future date based on the input .
DATE_TO_DAY - Returns the Day for the entered date.
DATE_COMPUTE_DAY - Returns weekday for a date
DATE_GET_WEEK - Returns week for a date
RP_CALC_DATE_IN_INTERVAL - Add days / months to a date
DAY_ATTRIBUTES_GET - Returns attributes for a range of dates specified
MONTHS_BETWEEN_TWO_DATES - To get the number of months between the two dates.
END_OF_MONTH_DETERMINE_2 - Determines the End of a Month.
HR_HK_DIFF_BT_2_DATES -Find the difference between two dates in years, months and days.
FIMA_DAYS_AND_MONTHS_AND_YEARS - Find the difference between two dates in years, months and days.
WEEK_GET_FIRST_DAY - Get the first day of the week
SD_CALC_DURATION_FROM_DATETIME - Find the difference between two date/time and report the difference in hours
L_MC_TIME_DIFFERENCE - Find the time difference between two date/time
HR_99S_INTERVAL_BETWEEN_DATES - Difference between two dates in days, weeks, months
LAST_DAY_OF_MONTHS - Returns the last day of the month
DATE_CHECK_PLAUSIBILITY - Check for the invalid date.
DATE_2D_TO_4D_CONVERSION - Year entry: 2-character to 4-character.
DAY_IN_WEEK - Input date and will give the name of the day 1-monday,2-Tuesday....
SD_DATETIME_DIFFERENCE - Give the difference in Days and Time for 2 dates -
The engineer turned up as arranged a week ago to connect infinity. I wanted the main box upstairs rather than in my dining room but that was not an issue as there are 2 cables at the incoming point so easy to use the right one.
Engineer did as asked, tested and reported 60 meg connection happy days - when I got home it was 29 meg down and 2.5 meg up - reset modem and the upload improved to 13 meg so crossed my fingers it would go up? Instead on Saturday the connection failed completely and after talking to support they acknowledged a line fault . I will say that despite having to go through the basic of resetting the modem etc CS was good.
Sunday checked the connections myself and found the master wired as a spur so no filters were actually connected to the phone wiring! BT engineer arrived Monday and identified the same thing and proceeded to move the master back down to the dining room and spurred the data up to the modem. As he used the master downstairs he now did not have a suitable faceplate so hard wired the modem into the box - not good if you actually want to unplug it! I can easily sort that myself by connecting incoming line back upstairs, moving the master socket and connecting the rest of the extensions on another pair but it would have been nice if one of the BT engineers could have worked this out?
And now I have half the expected speed at 7meg up and 27meg down!! I know the line can handle a lot more both because that is half what was predicted and I ran at over 16 meg on my o2 connection showing the line is very good.
So now I have to wait another week to let it 'settle down'. I have no expectation it will increase on it's own so it will be more time wasted and overall a very disappointing first week with BT.Well after another 4 weeks the speed has not come close to expectations (particularaly upload speed) and while not hopeless, this performance would not have persuaded me to move from a rock steady ADSL2 which gave over 16mb of the up to speed of 20Mb. I might as well save the moneyand move to the cheaper 38Mb package!
I was sold on the estimate below but the actual speeds are consistant but well short of expectations. I have disconncected the house wiring and actually renewed a couple of connections to eliminate the possiblility of interfereance and ran this test with the wireless off at the HH but nothing has helped so I suspect there is an issue elsewhere?
Any suggestions or will I just have to wait 17 months and change providor??
Superfast fibre optic broadbandGreat news! You are eligible for superfast BT Infinity.
57.2Mb download
15.7Mb upload
Actual performance
1. Best Effort Test: -provides background information.
Download Speed
39.43 Mbps
0 Mbps 0 Mbps
Max Achievable Speed
Download speed achieved during the test was - 39.43 Mbps
For your connection, the acceptable range of speeds is 12 Mbps-0 Mbps.
IP Profile for your line is - 41.22 Mbps
2. Upstream Test: -provides background information.
Upload Speed
6.83 Mbps
0 Mbps 20 Mbps
Max Achievable Speed
Upload speed achieved during the test was - 6.83Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps -
Get reports content of earlier versions through ABAP code.
Hi All,
I want to get contents of report in an internal table for earlier versions.
Do we have any standard table/FM to get the report's content in our program?
To be more specific I want to know how much line of code added/modified in each versions.
Thanks.
Regards,
PKhi pranshu,
I find your requirement very different.
i have few doubts, when u mean contents u mean lines of code or the output records of the report.
if u mean lines of code modified u want to know, u have version management where u can find the changed lines of code,since the inception of the program.
regards, -
Why didn't no one lay Fiber in the streets back in the early days
Hey All, I'm curious as to why didn't no one lay Fiber into the ground in the year 2000 and start the fast network from that day Phone lines were never meant to run internet? considering so many issues during the past 15 years Didn't they realise back then that it have to be replaced with proper cables/Fiber in the ground Just curious to hear everyone else's response to this.
I can give you several reasons: 1: when they decided to sell off public owned phone services they screwed up and sold the physical infastructure as well as the customer base. 2: the competitiors argued that it was pointless to double up all the infrastruture and should just pay a rental to the owner of that infrastrucure ( hence why there is some optus and some telstra cable broadband options in limited areas and the reason also why they didnt expand futher) 3: Telstra (which really should have been a customers only business) wasnt going to spend the millions or billions to upgrade the lines out of their own pockets for the competitors to gain advantage over them
-
How to Calculate the Time Between two days in ABAP
Hi,
I have one scenario like i need to calculate the time between two days please can you suggest me.
Thanks,
HarinathHi Peeleti,
Check this code,
DATA : DATE1 LIKE SY-DATUM VALUE '19830125',
DATE2 LIKE SY-DATUM VALUE '20070219',
DAYS1 TYPE I,
WEEK1 TYPE I,
MONTH1 TYPE I,
YEAR1 TYPE I,
C_YEARS1 TYPE I.
CALL FUNCTION 'HR_99S_INTERVAL_BETWEEN_DATES'
EXPORTING
BEGDA = DATE1
endda = DATE2
TAB_MODE = ' '
IMPORTING
DAYS = DAYS1
C_WEEKS =
C_MONTHS = C_YEARS1
C_YEARS = C_YEARS1
WEEKS = WEEK1
MONTHS = MONTH1
YEARS = YEAR1.
D_MONTHS =
MONTH_TAB =
*WRITE : / 'DAYS = ', DAYS1,
/ 'WEEKS = ',WEEK1,
/ 'MONTHS = ', MONTH1,
/ 'YEARS = ', YEAR1.
Using this code you can calculate the No Of Days Between two dates. Based On days you will easily calculate the Hour. [ No of days * 24 ].
Thanks.
Reward If helpful. -
SAY NO TO FEMALE GENITAL MULTILATION. a copy bought goes a long way to save a young African woman from Tears
Well after another 4 weeks the speed has not come close to expectations (particularaly upload speed) and while not hopeless, this performance would not have persuaded me to move from a rock steady ADSL2 which gave over 16mb of the up to speed of 20Mb. I might as well save the moneyand move to the cheaper 38Mb package!
I was sold on the estimate below but the actual speeds are consistant but well short of expectations. I have disconncected the house wiring and actually renewed a couple of connections to eliminate the possiblility of interfereance and ran this test with the wireless off at the HH but nothing has helped so I suspect there is an issue elsewhere?
Any suggestions or will I just have to wait 17 months and change providor??
Superfast fibre optic broadbandGreat news! You are eligible for superfast BT Infinity.
57.2Mb download
15.7Mb upload
Actual performance
1. Best Effort Test: -provides background information.
Download Speed
39.43 Mbps
0 Mbps 0 Mbps
Max Achievable Speed
Download speed achieved during the test was - 39.43 Mbps
For your connection, the acceptable range of speeds is 12 Mbps-0 Mbps.
IP Profile for your line is - 41.22 Mbps
2. Upstream Test: -provides background information.
Upload Speed
6.83 Mbps
0 Mbps 20 Mbps
Max Achievable Speed
Upload speed achieved during the test was - 6.83Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps -
Dear ALL,
Myself Kiran from Bangalore, working as Software Developer(PHP/Mysql) having 3 year of total experience.
I always had a dream to learn some Technical modules like ABAP or BI and to become SAP consultant from my initial days of my career.
I also took opinions from SAP gurus through discussion forum,But they said in-order to enter into SAP field one should have domain experience . so i just dropped my idea of entering SAP field.
But after 3 years of programming , i just wanted to learn SAP ABAP/BI/BW , so i need to know answers for fallowing question.
1. Which one suites me either SAP ABAP or BI suites me ? Considering my past 3 years of programming experience?
2. What are the ways that i can enter in to SAP field in technical modules?
This is link to discussion that i had it in earlier days
http://sap.ittoolbox.com/groups/career/sap-career/what-to-choose-sap-or-php-4473164
Thanks in Advance,
Regards,
Kiran YuvarajHello Kiran,
Getting a job in SAP as a fresher ( ABAP / BI / Any module) is infact a difficult task ..
That depends upon totally on you and You only..Yes, Based on your hard work, dedication,
sincerity and the level of efforts you put in, you can get into SAP..The entry is only
difficult..Once you enter you can sustain..But that too depends on your interest alone..
Simply Saying, IF You want yourself to be a Strong Competent, you need to Work Hard..thats it..
Coming to your Question,
In Market, The Openings for BI as a FRESHER is low compared to ABAP..
Hope the above statement answers your question.. Dont confuse too much..Get suggestions from
the Reliable People you know and take off..But I Clearly mention the market situation..Rest is in you
Hands..Dont Worry..Take Clear decision and Lets Start..All is Well ..
Warm Regards,
Nellai Muthu.. -
Abap basics material documents
Hi Gurus,
i am intrested to learn basic in Abap i want to make my carrrier in it so i kindky request you to plz send material my [email protected]
Thanks in Advance,
Edited by: Krishna on Apr 23, 2008 2:16 PM
Edited by: Krishna on Apr 23, 2008 2:17 PMHi....
Go for Siemens material. Check the following link:
http://www.sapbrainsonline.com/TUTORIALS/TECHNICAL/ABAP_tutorial.html
additional info
ABAP is one of many application-specific fourth-generation languages (4GLs) first developed in the 1980s. It was originally the report language for SAP R/2, a platform that enabled large corporations to build mainframe business applications for materials management and financial and management accounting. ABAP used to be an abbreviation of Allgemeiner Berichtsaufbereitungsprozessor, the German meaning of "generic report preparation processor", but was later renamed to Advanced Business Application Programming. ABAP was one of the first languages to include the concept of Logical Databases (LDBs), which provides a high level of abstraction from the basic database level.
The ABAP programming language was originally used by SAP developers to develop the SAP R/3 platform. It was also intended to be used by SAP customers to enhance SAP applications customers can develop custom reports and interfaces with ABAP programming. The language is fairly easy to learn for programmers but it is not a tool for direct use by non-programmers. Good programming skills, including knowledge of relational database design and preferably also of object-oriented concepts, are required to create ABAP programs.
ABAP remains the language for creating programs for the client-server R/3 system, which SAP first released in 1992. As computer hardware evolved through the 1990s, more and more of SAP's applications and systems were written in ABAP. By 2001, all but the most basic functions were written in ABAP. In 1999, SAP released an object-oriented extension to ABAP called ABAP Objects, along with R/3 release 4.6.
SAP's most recent development platform, NetWeaver, supports both ABAP and Java.
edit Implementation
edit Where does the ABAP Program Run?
All ABAP programs reside inside the SAP database. They are not stored in separate external files like Java or C++ programs. In the database all ABAP code exists in two forms: source code, which can be viewed and edited with the ABAP workbench, and "compiled" code ("generated" code is the more correct technical term), which is loaded and interpreted by the ABAP runtime system. Code generation happens implicitly when a unit of ABAP code is first invoked. If the source code is changed later or if one of the data objects accessed by the program has changed (e.g. fields were added to a database table), then the code is automatically regenerated.
ABAP programs run in the SAP application server, under control of the runtime system, which is part of the SAP kernel. The runtime system is responsible for processing ABAP statements, controlling the flow logic of screens and responding to events (such as a user clicking on a screen button). A key component of the ABAP runtime system is the Database Interface, which turns database-independent ABAP statements ("Open SQL") into statements understood by the underlying DBMS ("Native SQL"). The database interface handles all the communication with the relational database on behalf of ABAP programs; it also contains extra features such as buffering of frequently accessed data in the local memory of the application server.
Basis
Basis sits between ABAP/4 and Operating system.Basis is like an operating system for R/3. It sits between the ABAP/4 code and the computer's operating system. SAP likes to call it middleware because it sits in the middle, between ABAP/4 and the operating system. Basis sits between ABAP/4 and the operating system. ABAP/4 cannot run directly on an operating system. It requires a set of programs (collectively called Basis) to load, interpret, and buffer its input and output. Basis, in some respects, is like the Windows environment. Windows starts up, and while running it provides an environment in which Windows programs can run. Without Windows, programs written for the Windows environment cannot run. Basis is to ABAP/4 programs as Windows is to Windows programs. Basis provides the runtime environment for ABAP/4 programs. Without Basis, ABAP/4 programs cannot run. When the operator starts up R/3, you can think of him as starting up Basis. Basis is a collection of R/3 system programs that present you with an interface. Using this interface the user can start ABAP/4 programs. To install Basis, an installer runs the program r3inst at the command-prompt level of the operating system. Like most installs, this creates a directory structure and copies a set of executables into it. These executables taken together as a unit form Basis.
To start up the R/3 system, the operator enters the startsap command. The Basis executables start up and stay running, accepting requests from the user to run ABAP/4 programs.
ABAP/4 programs run within the protective Basis environment; they are not executables that run on the operating system. Instead, Basis reads ABAP/4 code and interprets it into operating system instructions. ABAP/4 programs do not access operating system functions directly. Instead, they use Basis functions to perform file I/O and display data in windows. This level of isolation from the operating system enables ABAP/4 programs to be ported without modification to any system that supports R/3. This buffering is built right into the ABAP/4 language itself and is actually totally transparent to the programmer.
Basis makes ABAP/4 programs portable. The platforms that R/3 can run on are shown in Table. For example, if you write an ABAP/4 program on Digital UNIX with an Informix database and an OSF/Motif interface, that same program should run without modification on a Windows NT machine with an Oracle database and a Windows 95 interface. Or, it could run on an AS/400 with a DB2 database using OS/2 as the front-end.
SAP also provides a suite of tools for administering the Basis system. These tools perform tasks such as system performance monitoring, configuration, and system maintenance. To access the Basis administration tools from the main menu, choose the path Tools->Administration.
Platforms and Databases Supported by R/3
Operating Systems Supported Hardware Supported Front-Ends Supported Databases
AIX SINIX IBM SNI SUN Win 3.1/95/NT DB2 for AIX
SOLARIS HP-UX Digital HP OSF/Motif Informix-Online
Digital-UNIX Bull OS/2 Oracle 7.1
Windows NT AT&T Compaq Win 3.1/95/NT Oracle 7.1
Bull/Zenith OSF/Motif SQL Server 6.0
HP (Intel) SNI OS/2 ADABAS D
OS/400 AS/400 Win95 OS/2 DB2/400
edit SAP Systems and Landscapes
All SAP data exists and all SAP software runs in the context of an SAP system. A system consists of a central relational database and one or more application servers ("instances") accessing the data and programs in this database. A SAP system contains at least one instance but may contain more, mostly for reasons of sizing and performance. In a system with multiple instances, load balancing mechanisms ensure that the load is spread evenly over the available application servers.
Installations of the Web Application Server (landscapes) typically consist of three systems: one for development, one for testing and quality assurance, and one for production. The landscape may contain more systems, e.g. separate systems for unit testing and pre-production testing, or it may contain fewer, e.g. only development and production, without separate QA; nevertheless three is the most common configuration. ABAP programs are created and undergo first testing in the development system. Afterwards they are distributed to the other systems in the landscape. These actions take place under control of the Change and Transport System (CTS), which is responsible for concurrency control (e.g. preventing two developers from changing the same code at the same time), version management and deployment of programs on the QA and production systems.
The Web Application Server consists of three layers: the database layer, the application layer and the presentation layer. These layers may run on the same or on different physical machines. The database layer contains the relational database and the database software. The application layer contains the instance or instances of the system. All application processes, including the business transactions and the ABAP development, run on the application layer. The presentation layer handles the interaction with users of the system. Online access to ABAP application servers can go via a proprietary graphical interface, the SAPGUI, or via a Web browser.
edit Transactions
We call an execution of an ABAP program using a transaction code a transaction. There are dialog, report, parameter, variant, and as of release 6.10, OO transactions. A transaction is started by entering the transaction code in the input field on the standard toolbar, or by means of the ABAP statements CALL TRANSACTION or LEAVE TO TRANSACTION. Transaction codes can also be linked to screen elements or menu entries. Selecting such an element will start the transaction.
A transaction code is simply a twenty-character name connected with a Dynpro, another transaction code, or, as of release 6.10, a method of an ABAP program. Transaction codes linked with Dynpros are possible for executable programs, module pools, and function groups. Parameter transactions and variant transactions are linked with other transaction codes. Transaction codes that are linked with methods are allowed for all program types that can contain methods. Transaction codes are maintained in transaction SE93.
So, a transaction is nothing more than the SAP way of program executionbut why is it called transaction? ABAP is a language for business applications and the most important features of business applications were and still are are transactions. Since in the early days of SAP, the execution of a program often meant the same thing as carrying out a business transaction, the terms transaction and transaction code were chosen for program execution. But never mix up the technical meaning of a transaction with business transactions. For business transactions, it is the term LUW (Logical Unit of Work) that counts. And during one transaction (program execution), there can be many different LUWs.
Lets have a look at the different kind of transactions:
edit Dialog Transaction
These are the most common kind of transactions. The transaction code of a dialog transaction is linked to a Dynpro of an ABAP program. When the transaction is called, the respective program is loaded and the Dynpro is called. Therefore, a dialog transaction calls a Dynpro sequence rather than a program. Only during the execution of the Dynpro flow logic are the dialog modules of the ABAP program itself are called. The program flow can differ from execution to execution. You can even assign different dialog transaction codes to one program.
edit Parameter Transaction
In the definition of a parameter transaction code, a dialog transaction is linked with parameters. When you call a parameter transaction, the input fields of the initial Dynpro screen of the dialog transaction are filled with parameters. The display of the initial screen can be inhibited by specifying all mandatory input fields as parameters of the transaction.
edit Variant Transaction
In the definition of a variant transaction code, a dialog transaction is linked with a transaction variant. When a variant transaction is accessed, the dialog transaction is called and executed with the transaction variant. In transaction variants, you can assign default values to the input fields on several Dynpro screens in a transaction, change the attributes of screen elements, and hide entire screens. Transaction variants are maintained in transaction SHD0.
edit Report Transaction
A report transaction is the transaction code wrapping for starting the reporting process. The transaction code of a report transaction must be linked with the selection screen of an executable program. When you execute a report transaction, the runtime environment internally executes the ABAP statement SUBMITmore to come on that.
edit OO Transaction
A new kind of transaction as of release 6.10. The transaction code of an OO transaction is linked with a method of a local or global class. When the transaction is called, the corresponding program is loaded, for instance methods an object of the class is generated and the method is executed.
edit Types of ABAP programs
In ABAP, there are two different types of programs:
edit Report programs(Executable pools)
A Sample ReportReport programs AKA Executable pools follow a relatively simple programming model whereby a user optionally enters a set of parameters (e.g. a selection over a subset of data) and the program then uses the input parameters to produce a report in the form of an interactive list. The output from the report program is interactive because it is not a passive display; instead it enables the user, through ABAP language constructs, to obtain a more detailed view on specific data records via drill-down functions, or to invoke further processing through menu commands, for instance to sort the data in a different way or to filter the data according to selection criteria. This method of presenting reports has great advantages for users who must deal with large quantities of information and must also have the ability to examine this information in highly flexible ways, without being constrained by the rigid formatting or unmanageable size of "listing-like" reports. The ease with which such interactive reports can be developed is one of the most striking features of the ABAP language.
The term "report" is somewhat misleading in the sense that it is also possible to create report programs that modify the data in the underlying database instead of simply reading it.
A customized screen created using Screen Painter,which is one of the tool available in ABAP workbench(T-code = SE51).
edit Online programs
Online programs (also called module pools) do not produce lists. These programs define more complex patterns of user interaction using a collection of screens. The term screen refers to the actual, physical image that the users sees. Each screen also has a flow logic; this refers to the ABAP code invoked by the screens, i.e. the logic that initializes screens, responds to a users requests and controls the sequence between the screens of a module pool. Each screen has its own Flow Logic, which is divided into a "PBO" (Process Before Output) and "PAI" (Process After Input) section. In SAP documentation the term dynpro (dynamic program) refers to the combination of the screen and its Flow Logic.
Online programs are not invoked directly by their name, but are associated with a transaction code. Users can then invoke them through customizable, role-dependent, transaction menus.
Apart from reports and online programs, it is also possible to develop sharable code units such as class libraries, function libraries and subroutine pools.
edit Subroutine Pools
Subroutine pools, as the name implies, were created to contain selections of subroutines that can be called externally from other programs. Before release 6.10, this was the only way subroutine pools could be used. But besides subroutines, subroutine pools can also contain local classes and interfaces. As of release 6.10, you can connect transaction codes to methods. Therefore, you can now also call subroutine pools via transaction codes. This is the closest to a Java program you can get in ABAP: a subroutine pool with a class containing a method say main connected to a transaction code!
edit Type Pools
Type pools are the precursors to general type definitions in the ABAP Dictionary. Before release 4.0, only elementary data types and flat structures could be defined in the ABAP Dictionary. All other types that shouldve been generally available had to be defined with TYPES in type pools. As of release 4.0, type pools were only necessary for constants. As of release 6.40, constants can be declared in the public sections of global classes and type pools can be replaced by global classes.
edit Class Pools
Class pools serve as containers for exactly one global class. Besides the global class, they can contain global types and local classes/interfaces to be used in the global class. A class pool is loaded into memory by using one of its components. For example, a public method can be called from any ABAP program or via a transaction code connected to the method. You maintain class pools in the class builder.
edit Interface Pools
Interface pools serve as containers for exactly one global interfacenothing more and nothing less. You use an interface pool by implementing its interface in classes and by creating reference variables with the type of its interface. You maintain interface pools in the class builder.
edit ABAP Workbench
The ABAP Workbench contains different tools for editing Repository objects. These tools provide you with a wide range of assistance that covers the entire software development cycle. The most important tools for creating and editing Repository objects are:
ABAP Editor for writing and editing program code
ABAP Dictionary for processing database table definitions and retrieving global types
Menu Painter for designing the user interface (menu bar, standard toolbar, application toolbar, function key assignment)
Screen Painter for designing screens (dynamic programs) for user dialogs
Function Builder for displaying and processing function modules (routines with defined interfaces that are available throughout the system)
Class Builder for displaying and processing ABAP Objects classes
edit The ABAP Dictionary
Enforces data integrity
Manages data definitions without redundancy
Is tightly integrated with the rest of the ABAP/4 Development Workbench.
Enforcing data integrity is the process of ensuring that data entered into the system is logical, complete, and consistent. When data integrity rules are defined in the ABAP/4 Dictionary, the system automatically prevents the entry of invalid data. Defining the data integrity rules at the dictionary level means they only have to be defined once, rather than in each program that accesses that data.
The following are examples of data lacking integrity:
A date field with a month value of 13
An order assigned to a customer number that doesnt exist
An order not assigned to a customer
Managing data definitions without redundancy is the process of linking similar information to the same data definition. For example, a customer database is likely to contain a customers ID number in several places. The ABAP Dictionary provides the capability of defining the characteristics of a customer ID number in only one place. That central definition then can be used for each instance of a customer ID number.
The ABAP Dictionarys integration with the rest of the development environment enables ABAP programs to automatically recognize the names and characteristics of dictionary objects.
Additionally, the system provides easy navigation between development objects and dictionary definitions. For example, as a programmer, you can double-click on the name of a dictionary object in your program code, and the system will take you directly to the definition of that object in the ABAP/4 Dictionary.
When a dictionary object is changed, a program that references the changed object will automatically reference the new version the next time the program runs. Because ABAP is interpreted, it is not necessary to recompile programs that reference changed dictionary objects.
edit ABAP Syntax
The syntax of the ABAP programming language consists of the following elements:
Statements
An ABAP program consists of individual ABAP statements. Each statement begins with a keyword and ends with a period.
edit "Hello World" PROGRAM
WRITE 'Hello World'.
This example contains two statements, one on each line. The keywords are PROGRAM and WRITE. The program displays a list on the screen. In this case, the list consists of the line "My First Program".
The keyword determines the category of the statement. For an overview of the different categories, refer to ABAP Statements.
edit Formatting ABAP Statements
ABAP has no format restrictions. You can enter statements in any format, so a statement can be indented, you can write several statements on one line, or spread a single statement over several lines.
You must separate words within a statement with at least one space. The system also interprets the end of line marker as a space.
The program fragment
PROGRAM TEST.
WRITE 'This is a statement'.
could also be written as follows:
PROGRAM TEST. WRITE 'This is a statement'.
or as follows:
PROGRAM
TEST.
WRITE
'This is a statement'.
Use this free formatting to make your programs easier to understand.
edit Special Case: Text Literals
Text literals are sequences of alphanumeric characters in the program code that are enclosed in quotation marks. If a text literal in an ABAP statement extends across more than one line, the following difficulties can occur:
All spaces between the quotation marks are interpreted as belonging to the text literal. Letters in text literals in a line that is not concluded with quotation marks are interpreted by the editor as uppercase. If you want to enter text literals that do not fit into a single line, you can use the & character to combine a succession of text literals into a single one.
The program fragment
PROGRAM TEST.
WRITE 'This
is
a statement'.
inserts all spaces between the quotation marks into the literal, and converts the letters to uppercase.
This program fragment
PROGRAM TEST.
WRITE 'This' &
' is ' &
'a statement'.
combines three text literals into one.
edit Chained Statements
The ABAP programming language allows you to concatenate consecutive statements with an identical first part into a chain statement.
To concatenate a sequence of separate statements, write the identical part only once and place a colon ( after it. After the colon, write the remaining parts of the individual statements, separating them with commas. Ensure that you place a period (.) after the last part to inform the system where the chain ends.
Statement sequence:
WRITE SPFLI-CITYFROM.
WRITE SPFLI-CITYTO.
WRITE SPFLI-AIRPTO.
Chain statement:
WRITE: SPFLI-CITYFROM, SPFLI-CITYTO, SPFLI-AIRPTO.
In the chain, a colon separates the beginning of the statement from the variable parts. After the colon or commas, you can insert any number of spaces.
You could, for example, write the same statement like this:
WRITE: SPFLI-CITYFROM,
SPFLI-CITYTO,
SPFLI-AIRPTO.
In a chain statement, the first part (before the colon) is not limited to the keyword of the statements.
Statement sequence:
SUM = SUM + 1.
SUM = SUM + 2.
SUM = SUM + 3.
SUM = SUM + 4.
Chain statement:
SUM = SUM + : 1, 2, 3, 4.
edit Comments
Comments are texts that you can write between the statements of your ABAP program to explain their purpose to a reader. Comments are distinguished by the preceding signs * (at the beginning of a line) and " (at any position in a line). If you want the entire line to be a comment, enter an asterisk (*) at the beginning of the line. The system then ignores the entire line when it generates the program. If you want part of a line to be a comment, enter a double quotation mark (") before the comment. The system interprets comments indicated by double quotation marks as spaces.
PROGRAM SAPMTEST *
WRITTEN BY KARL BYTE, 06/27/1995 *
LAST CHANGED BY RITA DIGIT, 10/01/1995 *
TASK: DEMONSTRATION *
PROGRAM SAPMTEST.
DECLARATIONS *
DATA: FLAG " GLOBAL FLAG
NUMBER TYPE I " COUNTER
PROCESSING BLOCKS *
Advantages of ABAP over Contemporary languages
ABAP OBJECTS
Object orientation in ABAP is an extension of the ABAP language that makes available the advantages of object-oriented programming, such as encapsulation, interfaces, and inheritance. This helps to simplify applications and make them more controllable.
ABAP Objects is fully compatible with the existing language, so you can use existing statements and modularization units in programs that use ABAP Objects, and can also use ABAP Objects in existing ABAP programs.
edit ABAP Statements an Overview
The first element of an ABAP statement is the ABAP keyword. This determines the category of the statement. The different statement categories are as follows:
edit Declarative Statements
These statements define data types or declare data objects which are used by the other statements in a program or routine. The collected declarative statements in a program or routine make up its declaration part.
Examples of declarative keywords:
TYPES, DATA, TABLES
edit Modularization Statements
These statements define the processing blocks in an ABAP program.
The modularization keywords can be further divided into:
· Defining keywords
You use statements containing these keywords to define subroutines, function modules, dialog modules and methods. You conclude these processing blocks using the END statements.
Examples of definitive keywords:
METHOD ... ENDMETHOD, FUNCTION ... ENDFUNCTION, MODULE ... ENDMODULE.
· Event keywords
You use statements containing these keywords to define event blocks. There are no special statements to conclude processing blocks - they end when the next processing block is introduced.
Examples of event key words:
AT SELECTION SCREEN, START-OF-SELECTION, AT USER-COMMAND
edit Control Statements
You use these statements to control the flow of an ABAP program within a processing block according to certain conditions.
Examples of control keywords:
IF, WHILE, CASE
edit Call Statements
You use these statements to call processing blocks that you have already defined using modularization statements. The blocks you call can either be in the same ABAP program or in a different program.
Examples of call keywords:
CALL METHOD, CALL TRANSACTION, SUBMIT, LEAVE TO
Operational Statements These keywords process the data that you have defined using declarative statements.
Examples of operational keywords:
MOVE, ADD
edit Unique Concept of Internal Table in ABAP
Internal tables provide a means of taking data from a fixed structure and storing it in working memory in ABAP. The data is stored line by line in memory, and each line has the same structure. In ABAP, internal tables fulfill the function of arrays. Since they are dynamic data objects, they save the programmer the task of dynamic memory management in his or her programs. You should use internal tables whenever you want to process a dataset with a fixed structure within a program. A particularly important use for internal tables is for storing and formatting data from a database table within a program. They are also a good way of including very complicated data structures in an ABAP program.
Like all elements in the ABAP type concept, internal tables can exist both as data types and as data objects A data type is the abstract description of an internal table, either in a program or centrally in the ABAP Dictionary, that you use to create a concrete data object. The data type is also an attribute of an existing data object.
edit Internal Tables as Data Types
Internal tables and structures are the two structured data types in ABAP. The data type of an internal table is fully specified by its line type, key, and table type.
edit Line type
The line type of an internal table can be any data type. The data type of an internal table is normally a structure. Each component of the structure is a column in the internal table. However, the line type may also be elementary or another internal table.
edit Key
The key identifies table rows. There are two kinds of key for internal tables - the standard key and a user-defined key. You can specify whether the key should be UNIQUE or NON-UNIQUE. Internal tables with a unique key cannot contain duplicate entries. The uniqueness depends on the table access method.
If a table has a structured line type, its default key consists of all of its non-numerical columns that are not references or themselves internal tables. If a table has an elementary line type, the default key is the entire line. The default key of an internal table whose line type is an internal table, the default key is empty.
The user-defined key can contain any columns of the internal table that are not references or themselves internal tables. Internal tables with a user-defined key are called key tables. When you define the key, the sequence of the key fields is significant. You should remember this, for example, if you intend to sort the table according to the key.
edit Table type
The table type determines how ABAP will access individual table entries. Internal tables can be divided into three types:
Standard tables have an internal linear index. From a particular size upwards, the indexes of internal tables are administered as trees. In this case, the index administration overhead increases in logarithmic and not linear relation to the number of lines. The system can access records either by using the table index or the key. The response time for key access is proportional to the number of entries in the table. The key of a standard table is always non-unique. You cannot specify a unique key. This means that standard tables can always be filled very quickly, since the system does not have to check whether there are already existing entries.
Sorted tables are always saved sorted by the key. They also have an internal index. The system can access records either by using the table index or the key. The response time for key access is logarithmically proportional to the number of table entries, since the system uses a binary search. The key of a sorted table can be either unique or non-unique. When you define the table, you must specify whether the key is to be unique or not. Standard tables and sorted tables are known generically as index tables.
Hashed tables have no linear index. You can only access a hashed table using its key. The response time is independent of the number of table entries, and is constant, since the system access the table entries using a hash algorithm. The key of a hashed table must be unique. When you define the table, you must specify the key as UNIQUE.
edit Generic Internal Tables
Unlike other local data types in programs, you do not have to specify the data type of an internal table fully. Instead, you can specify a generic construction, that is, the key or key and line type of an internal table data type may remain unspecified. You can use generic internal tables to specify the types of field symbols and the interface parameters of procedures . You cannot use them to declare data objects.
edit Internal Tables as Dynamic Data Objects
Data objects that are defined either with the data type of an internal table, or directly as an internal table, are always fully defined in respect of their line type, key and access method. However, the number of lines is not fixed. Thus internal tables are dynamic data objects, since they can contain any number of lines of a particular type. The only restriction on the number of lines an internal table may contain are the limits of your system installation. The maximum memory that can be occupied by an internal table (including its internal administration) is 2 gigabytes. A more realistic figure is up to 500 megabytes. An additional restriction for hashed tables is that they may not contain more than 2 million entries. The line types of internal tables can be any ABAP data types - elementary, structured, or internal tables. The individual lines of an internal table are called table lines or table entries. Each component of a structured line is called a column in the internal table.
edit Choosing a Table Type
The table type (and particularly the access method) that you will use depends on how the typical internal table operations will be most frequently executed.
edit Standard tables
This is the most appropriate type if you are going to address the individual table entries using the index. Index access is the quickest possible access. You should fill a standard table by appending lines (ABAP APPEND statement), and read, modify and delete entries by specifying the index (INDEX option with the relevant ABAP command). The access time for a standard table increases in a linear relationship with the number of table entries. If you need key access, standard tables are particularly useful if you can fill and process the table in separate steps. For example, you could fill the table by appending entries, and then sort it. If you use the binary search option with key access, the response time is logarithmically proportional to the number of table entries.
edit Sorted tables
This is the most appropriate type if you need a table which is sorted as you fill it. You fill sorted tables using the INSERT statement. Entries are inserted according to the sort sequence defined through the table key. Any illegal entries are recognized as soon as you try to add them to the table. The response time for key access is logarithmically proportional to the number of table entries, since the system always uses a binary search. Sorted tables are particularly useful for partially sequential processing in a LOOP if you specify the beginning of the table key in the WHERE condition.
edit Hashed tables
This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index. The response time for key access remains constant, regardless of the number of table entries. Like database tables, hashed tables always have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for processing large amounts of data.
edit Advanced Topics
edit Batch Input: Concepts
Processing Sessions
The above figure shows how a batch input session works.A batch input session is a set of one or more calls to transactions along with the data to be processed by the transactions. The system normally executes the transactions in a session non-interactively, allowing rapid entry of bulk data into an R/3 System.
A session records transactions and data in a special format that can be interpreted by the R/3 System. When the System reads a session, it uses the data in the session to simulate on-line entry of transactions and data. The System can call transactions and enter data using most of the facilities that are available to interactive users.
For example, the data that a session enters into transaction screens is subject to the same consistency checking as in normal interactive operation. Further, batch input sessions are subject to the user-based authorization checking that is performed by the system.
edit Advantages of ABAP over Contemporary languages
ABAP Objects offers a number of advantages, even if you want to continue using procedural programming. If you want to use new ABAP features, you have to use object-oriented interfaces anyway.
Sharing Data: With ABAP shared objects, you can aggregate data once at a central location and the different users and programs can then access this data without the need for copying.
Exception Handling: With the class-based exception concept of ABAP, you can define a special control flow for a specific error situation and provide the user with information about the error.
Developing Persistency: For permanent storage of data in ABAP, you use relational database tables by means of database-independent Open SQL, which is integrated in ABAP. However, you can also store selected objects transparently or access the integrated database or other databases using proprietary SQL.
Connectivity and Interoperability: The Exchange Infrastructure and Web services are the means by which developers can implement a service-oriented architecture. With Web services, you can provide and consume services independently of implementation or protocol. Furthermore, you can do so within NetWeaver and in the communication with other systems. With the features of the Exchange Infrastructure, you can enable, manage, and adapt integration scenarios between systems.
Making Enhancements: With the Enhancement Framework, you can enhance programs, function modules, and global classes without modification as well as replace existing code. The Switch Framework enables you activate only specific development objects or enhancements in a system.
edit Considerable Aspects
It follows a list of aspects to be considered during development. The list of course is not complete.
edit Dynpro persistence
When implementing dynpros one has to care for himself to read out and persist the necessary fields. Recently it happened to me that I forgot to include a field into the UPDATE-clause which is an error not so easy to uncover if you have other problems to be solved in the same package. Here, tool-support or built-in mechanisms would help.
The developer could help himself out by creating something like a document containing a cookbook or guide in which parts of a dynpro logic one has to care about persistence. With that at hand, it would be quite easy finding those bugs in short time. Maybe a report scanning for the definition of the dynpro fields to be persisted could scan the code automatically, too.
edit Memory Cache
It should be common-sense that avoiding select-statements onto the database helps reducing the server load. For that the programmer either can resort to function modules if available. This maybe is the case for important tables. Or the programmer needs to implement his own logic using internal tables. Here, the standard software package could provide the developer with a tool or a mechanism auto-generating memory cached tables resp. function modules implementing this.
Sometimes buffering of database tables could be used, if applicable. But that would require an effort in customizing the system and could drain down system performance overall, especially if a table is involved that has a central role.
edit Interfaces
It should be noticed that some function modules available have an incomplete interface. That means, the interface does not include all parameters evaluated by the logic of the function module. For example, global variables from within the function group could be read out, which cannot be influenced by the general caller. Or memory parameters are used internally to feed the logic with further information.
One workaround here would be copying the relevant parts of the logic to a newly created function module and then adapt it to the own context. This sometimes is possible, maybe if the copied code is not too lengthy and only a few or no calls to other logic is part of it.
A modification of the SAP code could be considered, if the modification itself is unavoidable (or another solution would be not justifiable by estimated effort to spend on it) and if the location of the modification seems quite safe against future upgrades or hot fixes. The latter is something that could be evaluated by contacting the SAP hotline or working with OSS message (searching thru existing one, perhaps open a new one).
edit Example
'From SAP NetWeaver:'
set an exclusive lock at level object-type & object-id
IF NOT lf_bapi_error = true.
IF ( NOT istourhd-doc_type IS INITIAL ) AND
( NOT istourhd-doc_id IS INITIAL )
CALL FUNCTION 'ENQUEUE_/DSD/E_HH_RAREF'
EXPORTING
obj_typ = istourhd-doc_type
obj_id = istourhd-doc_id
EXCEPTIONS
foreign_lock = 1
system_failure = 2
OTHERS = 3.
IF sy-subrc 0.
terminate processing...
lf_bapi_error = true.
...and add message to return table
PERFORM set_msg_to_bapiret2
USING sy-msgid gc_abort sy-msgno
sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4
gc_istourhd gc_enqueue_refdoc space
CHANGING lt_return.
ENDIF.
ENDIF.
ENDIF. " bapi error
edit Example Report(Type - ALV(Advanced List Viewer))
REPORT Z_ALV_SIMPLE_EXAMPLE_WITH_ITAB .
*Simple example to use ALV and to define the ALV data in an internal
*table
*data definition
tables:
marav. "Table MARA and table MAKT
Data to be displayed in ALV
Using the following syntax, REUSE_ALV_FIELDCATALOG_MERGE can auto-
matically determine the fieldstructure from this source program
Data:
begin of imat occurs 100,
matnr like marav-matnr, "Material number
maktx like marav-maktx, "Material short text
matkl like marav-matkl, "Material group (so you can test to make
" intermediate sums)
ntgew like marav-ntgew, "Net weight, numeric field (so you can test to
"make sums)
gewei like marav-gewei, "weight unit (just to be complete)
end of imat.
Other data needed
field to store report name
data i_repid like sy-repid.
field to check table length
data i_lines like sy-tabix.
Data for ALV display
TYPE-POOLS: SLIS.
data int_fcat type SLIS_T_FIELDCAT_ALV.
select-options:
s_matnr for marav-matnr matchcode object MAT1.
start-of-selection.
read data into table imat
select * from marav
into corresponding fields of table imat
where
matnr in s_matnr.
Check if material was found
clear i_lines.
describe table imat lines i_lines.
if i_lines lt 1.
Using hardcoded write here for easy upload
write: /
'No materials found.'.
exit.
endif.
end-of-selection.
To use ALV, we need a DDIC-structure or a thing called Fieldcatalogue.
The fieldcatalouge can be generated by FUNCTION
'REUSE_ALV_FIELDCATALOG_MERGE' from an internal table from any
report source, including this report.
Store report name
i_repid = sy-repid.
Create Fieldcatalogue from internal table
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
EXPORTING
I_PROGRAM_NAME = i_repid
I_INTERNAL_TABNAME = 'IMAT' "capital letters!
I_INCLNAME = i_repid
CHANGING
CT_FIELDCAT = int_fcat
EXCEPTIONS
INCONSISTENT_INTERFACE = 1
PROGRAM_ERROR = 2
OTHERS = 3.
*explanations:
I_PROGRAM_NAME is the program which calls this function
I_INTERNAL_TABNAME is the name of the internal table which you want
to display in ALV
I_INCLNAME is the ABAP-source where the internal table is defined
(DATA....)
CT_FIELDCAT contains the Fieldcatalouge that we need later for
ALV display
IF SY-SUBRC 0.
write: /
'Returncode',
sy-subrc,
'from FUNCTION REUSE_ALV_FIELDCATALOG_MERGE'.
ENDIF.
*This was the fieldcatlogue
Call for ALV list display
CALL FUNCTION 'REUSE_ALV_LIST_DISPLAY'
EXPORTING
I_CALLBACK_PROGRAM = i_repid
IT_FIELDCAT = int_fcat
TABLES
T_OUTTAB = imat
EXCEPTIONS
PROGRAM_ERROR = 1
OTHERS = 2.
*explanations:
I_CALLBACK_PROGRAM is the program which calls this function
IT_FIELDCAT (just made by REUSE_ALV_FIELDCATALOG_MERGE) contains
now the data definition needed for display
I_SAVE allows the user to save his own layouts
T_OUTTAB contains the data to be displayed in ALV
IF SY-SUBRC 0.
write: /
'Returncode',
sy-subrc,
'from FUNCTION REUSE_ALV_LIST_DISPLAY'.
ENDIF.
first learn basic programing afterwards
go through commands, statements , events, functional modules.....etc.
and implement these stuff, in programing,. and do practising.
Check the following links:
http://www.sapbrainsonline.com/TUTORIALS/TECHNICAL/ABAP_tutorial.html
http://sap-img.com/
http://sapabaplive.blogspot.com/2007/07/download-abap-in-21-days.html
http://help.sap.com/saphelp_40b/helpdata/en/4f/991f82446d11d189700000e8322d00/applet.htm
http://www.sapbrainsonline.com/TUTORIALS/TECHNICAL/ABAP_tutorial.html
http://www.esnips.com/web/SAPAbapCertificationDocs/
Start with this.Refer this
For BDC:
http://myweb.dal.ca/hchinni/sap/bdc_home.htm
https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/bdc&
http://www.sap-img.com/abap/learning-bdc-programming.htm
http://www.sapdevelopment.co.uk/bdc/bdchome.htm
http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm
http://help.sap.com/saphelp_47x200/helpdata/en/69/c250684ba111d189750000e8322d00/frameset.htm
http://www.sapbrain.com/TUTORIALS/TECHNICAL/BDC_tutorial.html
Check these link:
http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm
http://www.sap-img.com/abap/question-about-bdc-program.htm -
Give me some brief introduction on ABAP
Hi all
Give me some brief introduction on ABAPHi
Welcome to SDN
ABAP is one of many application-specific fourth-generation languages (4GLs) first developed in the 1980s. It was originally the report language for SAP R/2, a platform that enabled large corporations to build mainframe business applications for materials management and financial and management accounting. ABAP used to be an abbreviation of Allgemeiner Berichtsaufbereitungsprozessor, the German meaning of "generic report preparation processor", but was later renamed to Advanced Business Application Programming. ABAP was one of the first languages to include the concept of Logical Databases (LDBs), which provides a high level of abstraction from the basic database level.
The ABAP programming language was originally used by SAP developers to develop the SAP R/3 platform. It was also intended to be used by SAP customers to enhance SAP applications customers can develop custom reports and interfaces with ABAP programming. The language is fairly easy to learn for programmers but it is not a tool for direct use by non-programmers. Good programming skills, including knowledge of relational database design and preferably also of object-oriented concepts, are required to create ABAP programs.
ABAP remains the language for creating programs for the client-server R/3 system, which SAP first released in 1992. As computer hardware evolved through the 1990s, more and more of SAP's applications and systems were written in ABAP. By 2001, all but the most basic functions were written in ABAP. In 1999, SAP released an object-oriented extension to ABAP called ABAP Objects, along with R/3 release 4.6.
SAP's most recent development platform, NetWeaver, supports both ABAP and Java.
Implementation
Where does the ABAP Program Run?
All ABAP programs reside inside the SAP database. They are not stored in separate external files like Java or C++ programs. In the database all ABAP code exists in two forms: source code, which can be viewed and edited with the ABAP workbench, and "compiled" code ("generated" code is the more correct technical term), which is loaded and interpreted by the ABAP runtime system. Code generation happens implicitly when a unit of ABAP code is first invoked. If the source code is changed later or if one of the data objects accessed by the program has changed (e.g. fields were added to a database table), then the code is automatically regenerated.
ABAP programs run in the SAP application server, under control of the runtime system, which is part of the SAP kernel. The runtime system is responsible for processing ABAP statements, controlling the flow logic of screens and responding to events (such as a user clicking on a screen button). A key component of the ABAP runtime system is the Database Interface, which turns database-independent ABAP statements ("Open SQL") into statements understood by the underlying DBMS ("Native SQL"). The database interface handles all the communication with the relational database on behalf of ABAP programs; it also contains extra features such as buffering of frequently accessed data in the local memory of the application server.
Basis
Basis sits between ABAP/4 and Operating system.Basis is like an operating system for R/3. It sits between the ABAP/4 code and the computer's operating system. SAP likes to call it middleware because it sits in the middle, between ABAP/4 and the operating system. Basis sits between ABAP/4 and the operating system. ABAP/4 cannot run directly on an operating system. It requires a set of programs (collectively called Basis) to load, interpret, and buffer its input and output. Basis, in some respects, is like the Windows environment. Windows starts up, and while running it provides an environment in which Windows programs can run. Without Windows, programs written for the Windows environment cannot run. Basis is to ABAP/4 programs as Windows is to Windows programs. Basis provides the runtime environment for ABAP/4 programs. Without Basis, ABAP/4 programs cannot run. When the operator starts up R/3, you can think of him as starting up Basis. Basis is a collection of R/3 system programs that present you with an interface. Using this interface the user can start ABAP/4 programs. To install Basis, an installer runs the program r3inst at the command-prompt level of the operating system. Like most installs, this creates a directory structure and copies a set of executables into it. These executables taken together as a unit form Basis.
To start up the R/3 system, the operator enters the startsap command. The Basis executables start up and stay running, accepting requests from the user to run ABAP/4 programs.
ABAP/4 programs run within the protective Basis environment; they are not executables that run on the operating system. Instead, Basis reads ABAP/4 code and interprets it into operating system instructions. ABAP/4 programs do not access operating system functions directly. Instead, they use Basis functions to perform file I/O and display data in windows. This level of isolation from the operating system enables ABAP/4 programs to be ported without modification to any system that supports R/3. This buffering is built right into the ABAP/4 language itself and is actually totally transparent to the programmer.
Basis makes ABAP/4 programs portable. The platforms that R/3 can run on are shown in Table. For example, if you write an ABAP/4 program on Digital UNIX with an Informix database and an OSF/Motif interface, that same program should run without modification on a Windows NT machine with an Oracle database and a Windows 95 interface. Or, it could run on an AS/400 with a DB2 database using OS/2 as the front-end.
SAP also provides a suite of tools for administering the Basis system. These tools perform tasks such as system performance monitoring, configuration, and system maintenance. To access the Basis administration tools from the main menu, choose the path Tools->Administration.
Platforms and Databases Supported by R/3
Operating Systems Supported Hardware Supported Front-Ends Supported Databases
AIX SINIX IBM SNI SUN Win 3.1/95/NT DB2 for AIX
SOLARIS HP-UX Digital HP OSF/Motif Informix-Online
Digital-UNIX Bull OS/2 Oracle 7.1
Windows NT AT&T Compaq Win 3.1/95/NT Oracle 7.1
Bull/Zenith OSF/Motif SQL Server 6.0
HP (Intel) SNI OS/2 ADABAS D
OS/400 AS/400 Win95 OS/2 DB2/400
SAP Systems and Landscapes
All SAP data exists and all SAP software runs in the context of an SAP system. A system consists of a central relational database and one or more application servers ("instances") accessing the data and programs in this database. A SAP system contains at least one instance but may contain more, mostly for reasons of sizing and performance. In a system with multiple instances, load balancing mechanisms ensure that the load is spread evenly over the available application servers.
Installations of the Web Application Server (landscapes) typically consist of three systems: one for development, one for testing and quality assurance, and one for production. The landscape may contain more systems, e.g. separate systems for unit testing and pre-production testing, or it may contain fewer, e.g. only development and production, without separate QA; nevertheless three is the most common configuration. ABAP programs are created and undergo first testing in the development system. Afterwards they are distributed to the other systems in the landscape. These actions take place under control of the Change and Transport System (CTS), which is responsible for concurrency control (e.g. preventing two developers from changing the same code at the same time), version management and deployment of programs on the QA and production systems.
The Web Application Server consists of three layers: the database layer, the application layer and the presentation layer. These layers may run on the same or on different physical machines. The database layer contains the relational database and the database software. The application layer contains the instance or instances of the system. All application processes, including the business transactions and the ABAP development, run on the application layer. The presentation layer handles the interaction with users of the system. Online access to ABAP application servers can go via a proprietary graphical interface, the SAPGUI, or via a Web browser.
Transactions
We call an execution of an ABAP program using a transaction code a transaction. There are dialog, report, parameter, variant, and as of release 6.10, OO transactions. A transaction is started by entering the transaction code in the input field on the standard toolbar, or by means of the ABAP statements CALL TRANSACTION or LEAVE TO TRANSACTION. Transaction codes can also be linked to screen elements or menu entries. Selecting such an element will start the transaction.
A transaction code is simply a twenty-character name connected with a Dynpro, another transaction code, or, as of release 6.10, a method of an ABAP program. Transaction codes linked with Dynpros are possible for executable programs, module pools, and function groups. Parameter transactions and variant transactions are linked with other transaction codes. Transaction codes that are linked with methods are allowed for all program types that can contain methods. Transaction codes are maintained in transaction SE93.
So, a transaction is nothing more than the SAP way of program executionbut why is it called transaction? ABAP is a language for business applications and the most important features of business applications were and still are are transactions. Since in the early days of SAP, the execution of a program often meant the same thing as carrying out a business transaction, the terms transaction and transaction code were chosen for program execution. But never mix up the technical meaning of a transaction with business transactions. For business transactions, it is the term LUW (Logical Unit of Work) that counts. And during one transaction (program execution), there can be many different LUWs.
Lets have a look at the different kind of transactions:
Dialog Transaction
These are the most common kind of transactions. The transaction code of a dialog transaction is linked to a Dynpro of an ABAP program. When the transaction is called, the respective program is loaded and the Dynpro is called. Therefore, a dialog transaction calls a Dynpro sequence rather than a program. Only during the execution of the Dynpro flow logic are the dialog modules of the ABAP program itself are called. The program flow can differ from execution to execution. You can even assign different dialog transaction codes to one program.
Parameter Transaction
In the definition of a parameter transaction code, a dialog transaction is linked with parameters. When you call a parameter transaction, the input fields of the initial Dynpro screen of the dialog transaction are filled with parameters. The display of the initial screen can be inhibited by specifying all mandatory input fields as parameters of the transaction.
Variant Transaction
In the definition of a variant transaction code, a dialog transaction is linked with a transaction variant. When a variant transaction is accessed, the dialog transaction is called and executed with the transaction variant. In transaction variants, you can assign default values to the input fields on several Dynpro screens in a transaction, change the attributes of screen elements, and hide entire screens. Transaction variants are maintained in transaction SHD0.
Report Transaction
A report transaction is the transaction code wrapping for starting the reporting process. The transaction code of a report transaction must be linked with the selection screen of an executable program. When you execute a report transaction, the runtime environment internally executes the ABAP statement SUBMITmore to come on that.
OO Transaction
A new kind of transaction as of release 6.10. The transaction code of an OO transaction is linked with a method of a local or global class. When the transaction is called, the corresponding program is loaded, for instance methods an object of the class is generated and the method is executed.
Types of ABAP programs
In ABAP, there are two different types of programs:
Report programs(Executable pools)
A Sample ReportReport programs AKA Executable pools follow a relatively simple programming model whereby a user optionally enters a set of parameters (e.g. a selection over a subset of data) and the program then uses the input parameters to produce a report in the form of an interactive list. The output from the report program is interactive because it is not a passive display; instead it enables the user, through ABAP language constructs, to obtain a more detailed view on specific data records via drill-down functions, or to invoke further processing through menu commands, for instance to sort the data in a different way or to filter the data according to selection criteria. This method of presenting reports has great advantages for users who must deal with large quantities of information and must also have the ability to examine this information in highly flexible ways, without being constrained by the rigid formatting or unmanageable size of "listing-like" reports. The ease with which such interactive reports can be developed is one of the most striking features of the ABAP language.
The term "report" is somewhat misleading in the sense that it is also possible to create report programs that modify the data in the underlying database instead of simply reading it.
A customized screen created using Screen Painter,which is one of the tool available in ABAP workbench(T-code = SE51).
Online programs
Online programs (also called module pools) do not produce lists. These programs define more complex patterns of user interaction using a collection of screens. The term screen refers to the actual, physical image that the users sees. Each screen also has a flow logic; this refers to the ABAP code invoked by the screens, i.e. the logic that initializes screens, responds to a users requests and controls the sequence between the screens of a module pool. Each screen has its own Flow Logic, which is divided into a "PBO" (Process Before Output) and "PAI" (Process After Input) section. In SAP documentation the term dynpro (dynamic program) refers to the combination of the screen and its Flow Logic.
Online programs are not invoked directly by their name, but are associated with a transaction code. Users can then invoke them through customizable, role-dependent, transaction menus.
Apart from reports and online programs, it is also possible to develop sharable code units such as class libraries, function libraries and subroutine pools.
Subroutine Pools
Subroutine pools, as the name implies, were created to contain selections of subroutines that can be called externally from other programs. Before release 6.10, this was the only way subroutine pools could be used. But besides subroutines, subroutine pools can also contain local classes and interfaces. As of release 6.10, you can connect transaction codes to methods. Therefore, you can now also call subroutine pools via transaction codes. This is the closest to a Java program you can get in ABAP: a subroutine pool with a class containing a method say main connected to a transaction code!
Type Pools
Type pools are the precursors to general type definitions in the ABAP Dictionary. Before release 4.0, only elementary data types and flat structures could be defined in the ABAP Dictionary. All other types that shouldve been generally available had to be defined with TYPES in type pools. As of release 4.0, type pools were only necessary for constants. As of release 6.40, constants can be declared in the public sections of global classes and type pools can be replaced by global classes.
Class Pools
Class pools serve as containers for exactly one global class. Besides the global class, they can contain global types and local classes/interfaces to be used in the global class. A class pool is loaded into memory by using one of its components. For example, a public method can be called from any ABAP program or via a transaction code connected to the method. You maintain class pools in the class builder.
Interface Pools
Interface pools serve as containers for exactly one global interfacenothing more and nothing less. You use an interface pool by implementing its interface in classes and by creating reference variables with the type of its interface. You maintain interface pools in the class builder.
ABAP Workbench
The ABAP Workbench contains different tools for editing Repository objects. These tools provide you with a wide range of assistance that covers the entire software development cycle. The most important tools for creating and editing Repository objects are:
ABAP Editor for writing and editing program code
ABAP Dictionary for processing database table definitions and retrieving global types
Menu Painter for designing the user interface (menu bar, standard toolbar, application toolbar, function key assignment)
Screen Painter for designing screens (dynamic programs) for user dialogs
Function Builder for displaying and processing function modules (routines with defined interfaces that are available throughout the system)
Class Builder for displaying and processing ABAP Objects classes
The ABAP Dictionary
Enforces data integrity
Manages data definitions without redundancy
Is tightly integrated with the rest of the ABAP/4 Development Workbench.
Enforcing data integrity is the process of ensuring that data entered into the system is logical, complete, and consistent. When data integrity rules are defined in the ABAP/4 Dictionary, the system automatically prevents the entry of invalid data. Defining the data integrity rules at the dictionary level means they only have to be defined once, rather than in each program that accesses that data.
The following are examples of data lacking integrity:
A date field with a month value of 13
An order assigned to a customer number that doesnt exist
An order not assigned to a customer
Managing data definitions without redundancy is the process of linking similar information to the same data definition. For example, a customer database is likely to contain a customers ID number in several places. The ABAP Dictionary provides the capability of defining the characteristics of a customer ID number in only one place. That central definition then can be used for each instance of a customer ID number.
The ABAP Dictionarys integration with the rest of the development environment enables ABAP programs to automatically recognize the names and characteristics of dictionary objects.
Additionally, the system provides easy navigation between development objects and dictionary definitions. For example, as a programmer, you can double-click on the name of a dictionary object in your program code, and the system will take you directly to the definition of that object in the ABAP/4 Dictionary.
When a dictionary object is changed, a program that references the changed object will automatically reference the new version the next time the program runs. Because ABAP is interpreted, it is not necessary to recompile programs that reference changed dictionary objects.
ABAP Syntax
The syntax of the ABAP programming language consists of the following elements:
Statements
An ABAP program consists of individual ABAP statements. Each statement begins with a keyword and ends with a period.
"Hello World" PROGRAM
WRITE 'Hello World'.
This example contains two statements, one on each line. The keywords are PROGRAM and WRITE. The program displays a list on the screen. In this case, the list consists of the line "My First Program".
The keyword determines the category of the statement. For an overview of the different categories, refer to ABAP Statements.
Formatting ABAP Statements
ABAP has no format restrictions. You can enter statements in any format, so a statement can be indented, you can write several statements on one line, or spread a single statement over several lines.
You must separate words within a statement with at least one space. The system also interprets the end of line marker as a space.
The program fragment
PROGRAM TEST.
WRITE 'This is a statement'.
could also be written as follows:
PROGRAM TEST. WRITE 'This is a statement'.
or as follows:
PROGRAM
TEST.
WRITE
'This is a statement'.
Use this free formatting to make your programs easier to understand.
Special Case: Text Literals
Text literals are sequences of alphanumeric characters in the program code that are enclosed in quotation marks. If a text literal in an ABAP statement extends across more than one line, the following difficulties can occur:
All spaces between the quotation marks are interpreted as belonging to the text literal. Letters in text literals in a line that is not concluded with quotation marks are interpreted by the editor as uppercase. If you want to enter text literals that do not fit into a single line, you can use the & character to combine a succession of text literals into a single one.
The program fragment
PROGRAM TEST.
WRITE 'This
is
a statement'.
inserts all spaces between the quotation marks into the literal, and converts the letters to uppercase.
This program fragment
PROGRAM TEST.
WRITE 'This' &
' is ' &
'a statement'.
combines three text literals into one.
Chained Statements
The ABAP programming language allows you to concatenate consecutive statements with an identical first part into a chain statement.
To concatenate a sequence of separate statements, write the identical part only once and place a colon ( after it. After the colon, write the remaining parts of the individual statements, separating them with commas. Ensure that you place a period (.) after the last part to inform the system where the chain ends.
Statement sequence:
WRITE SPFLI-CITYFROM.
WRITE SPFLI-CITYTO.
WRITE SPFLI-AIRPTO.
Chain statement:
WRITE: SPFLI-CITYFROM, SPFLI-CITYTO, SPFLI-AIRPTO.
In the chain, a colon separates the beginning of the statement from the variable parts. After the colon or commas, you can insert any number of spaces.
You could, for example, write the same statement like this:
WRITE: SPFLI-CITYFROM,
SPFLI-CITYTO,
SPFLI-AIRPTO.
In a chain statement, the first part (before the colon) is not limited to the keyword of the statements.
Statement sequence:
SUM = SUM + 1.
SUM = SUM + 2.
SUM = SUM + 3.
SUM = SUM + 4.
Chain statement:
SUM = SUM + : 1, 2, 3, 4.
Comments
Comments are texts that you can write between the statements of your ABAP program to explain their purpose to a reader. Comments are distinguished by the preceding signs * (at the beginning of a line) and " (at any position in a line). If you want the entire line to be a comment, enter an asterisk (*) at the beginning of the line. The system then ignores the entire line when it generates the program. If you want part of a line to be a comment, enter a double quotation mark (") before the comment. The system interprets comments indicated by double quotation marks as spaces.
PROGRAM SAPMTEST *
WRITTEN BY KARL BYTE, 06/27/1995 *
LAST CHANGED BY RITA DIGIT, 10/01/1995 *
TASK: DEMONSTRATION *
PROGRAM SAPMTEST.
DECLARATIONS *
DATA: FLAG " GLOBAL FLAG
NUMBER TYPE I " COUNTER
PROCESSING BLOCKS *
Advantages of ABAP over Contemporary languages
ABAP OBJECTS
Object orientation in ABAP is an extension of the ABAP language that makes available the advantages of object-oriented programming, such as encapsulation, interfaces, and inheritance. This helps to simplify applications and make them more controllable.
ABAP Objects is fully compatible with the existing language, so you can use existing statements and modularization units in programs that use ABAP Objects, and can also use ABAP Objects in existing ABAP programs.
ABAP Statements an Overview
The first element of an ABAP statement is the ABAP keyword. This determines the category of the statement. The different statement categories are as follows:
Declarative Statements
These statements define data types or declare data objects which are used by the other statements in a program or routine. The collected declarative statements in a program or routine make up its declaration part.
Examples of declarative keywords:
TYPES, DATA, TABLES
Modularization Statements
These statements define the processing blocks in an ABAP program.
The modularization keywords can be further divided into:
· Defining keywords
You use statements containing these keywords to define subroutines, function modules, dialog modules and methods. You conclude these processing blocks using the END statements.
Examples of definitive keywords:
METHOD ... ENDMETHOD, FUNCTION ... ENDFUNCTION, MODULE ... ENDMODULE.
· Event keywords
You use statements containing these keywords to define event blocks. There are no special statements to conclude processing blocks - they end when the next processing block is introduced.
Examples of event key words:
AT SELECTION SCREEN, START-OF-SELECTION, AT USER-COMMAND
Control Statements
You use these statements to control the flow of an ABAP program within a processing block according to certain conditions.
Examples of control keywords:
IF, WHILE, CASE
Call Statements
You use these statements to call processing blocks that you have already defined using modularization statements. The blocks you call can either be in the same ABAP program or in a different program.
Examples of call keywords:
CALL METHOD, CALL TRANSACTION, SUBMIT, LEAVE TO
Operational Statements These keywords process the data that you have defined using declarative statements.
Examples of operational keywords:
MOVE, ADD
Unique Concept of Internal Table in ABAP
Internal tables provide a means of taking data from a fixed structure and storing it in working memory in ABAP. The data is stored line by line in memory, and each line has the same structure. In ABAP, internal tables fulfill the function of arrays. Since they are dynamic data objects, they save the programmer the task of dynamic memory management in his or her programs. You should use internal tables whenever you want to process a dataset with a fixed structure within a program. A particularly important use for internal tables is for storing and formatting data from a database table within a program. They are also a good way of including very complicated data structures in an ABAP program.
Like all elements in the ABAP type concept, internal tables can exist both as data types and as data objects A data type is the abstract description of an internal table, either in a program or centrally in the ABAP Dictionary, that you use to create a concrete data object. The data type is also an attribute of an existing data object.
Internal Tables as Data Types
Internal tables and structures are the two structured data types in ABAP. The data type of an internal table is fully specified by its line type, key, and table type.
Line type
The line type of an internal table can be any data type. The data type of an internal table is normally a structure. Each component of the structure is a column in the internal table. However, the line type may also be elementary or another internal table.
Key
The key identifies table rows. There are two kinds of key for internal tables - the standard key and a user-defined key. You can specify whether the key should be UNIQUE or NON-UNIQUE. Internal tables with a unique key cannot contain duplicate entries. The uniqueness depends on the table access method.
If a table has a structured line type, its default key consists of all of its non-numerical columns that are not references or themselves internal tables. If a table has an elementary line type, the default key is the entire line. The default key of an internal table whose line type is an internal table, the default key is empty.
The user-defined key can contain any columns of the internal table that are not references or themselves internal tables. Internal tables with a user-defined key are called key tables. When you define the key, the sequence of the key fields is significant. You should remember this, for example, if you intend to sort the table according to the key.
Table type
The table type determines how ABAP will access individual table entries. Internal tables can be divided into three types:
Standard tables have an internal linear index. From a particular size upwards, the indexes of internal tables are administered as trees. In this case, the index administration overhead increases in logarithmic and not linear relation to the number of lines. The system can access records either by using the table index or the key. The response time for key access is proportional to the number of entries in the table. The key of a standard table is always non-unique. You cannot specify a unique key. This means that standard tables can always be filled very quickly, since the system does not have to check whether there are already existing entries.
Sorted tables are always saved sorted by the key. They also have an internal index. The system can access records either by using the table index or the key. The response time for key access is logarithmically proportional to the number of table entries, since the system uses a binary search. The key of a sorted table can be either unique or non-unique. When you define the table, you must specify whether the key is to be unique or not. Standard tables and sorted tables are known generically as index tables.
Hashed tables have no linear index. You can only access a hashed table using its key. The response time is independent of the number of table entries, and is constant, since the system access the table entries using a hash algorithm. The key of a hashed table must be unique. When you define the table, you must specify the key as UNIQUE.
Generic Internal Tables
Unlike other local data types in programs, you do not have to specify the data type of an internal table fully. Instead, you can specify a generic construction, that is, the key or key and line type of an internal table data type may remain unspecified. You can use generic internal tables to specify the types of field symbols and the interface parameters of procedures . You cannot use them to declare data objects.
Internal Tables as Dynamic Data Objects
Data objects that are defined either with the data type of an internal table, or directly as an internal table, are always fully defined in respect of their line type, key and access method. However, the number of lines is not fixed. Thus internal tables are dynamic data objects, since they can contain any number of lines of a particular type. The only restriction on the number of lines an internal table may contain are the limits of your system installation. The maximum memory that can be occupied by an internal table (including its internal administration) is 2 gigabytes. A more realistic figure is up to 500 megabytes. An additional restriction for hashed tables is that they may not contain more than 2 million entries. The line types of internal tables can be any ABAP data types - elementary, structured, or internal tables. The individual lines of an internal table are called table lines or table entries. Each component of a structured line is called a column in the internal table.
Choosing a Table Type
The table type (and particularly the access method) that you will use depends on how the typical internal table operations will be most frequently executed.
Standard tables
This is the most appropriate type if you are going to address the individual table entries using the index. Index access is the quickest possible access. You should fill a standard table by appending lines (ABAP APPEND statement), and read, modify and delete entries by specifying the index (INDEX option with the relevant ABAP command). The access time for a standard table increases in a linear relationship with the number of table entries. If you need key access, standard tables are particularly useful if you can fill and process the table in separate steps. For example, you could fill the table by appending entries, and then sort it. If you use the binary search option with key access, the response time is logarithmically proportional to the number of table entries.
Sorted tables
This is the most appropriate type if you need a table which is sorted as you fill it. You fill sorted tables using the INSERT statement. Entries are inserted according to the sort sequence defined through the table key. Any illegal entries are recognized as soon as you try to add them to the table. The response time for key access is logarithmically proportional to the number of table entries, since the system always uses a binary search. Sorted tables are particularly useful for partially sequential processing in a LOOP if you specify the beginning of the table key in the WHERE condition.
Hashed tables
This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index. The response time for key access remains constant, regardless of the number of table entries. Like database tables, hashed tables always have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for processing large amounts of data.
Advanced Topics
Batch Input: Concepts
Processing Sessions
The above figure shows how a batch input session works.A batch input session is a set of one or more calls to transactions along with the data to be processed by the transactions. The system normally executes the transactions in a session non-interactively, allowing rapid entry of bulk data into an R/3 System.
A session records transactions and data in a special format that can be interpreted by the R/3 System. When the System reads a session, it uses the data in the session to simulate on-line entry of transactions and data. The System can call transactions and enter data using most of the facilities that are available to interactive users.
For example, the data that a session enters into transaction screens is subject to the same consistency checking as in normal interactive operation. Further, batch input sessions are subject to the user-based authorization checking that is performed by the system.
Advantages of ABAP over Contemporary languages
ABAP Objects offers a number of advantages, even if you want to continue using procedural programming. If you want to use new ABAP features, you have to use object-oriented interfaces anyway.
Sharing Data: With ABAP shared objects, you can aggregate data once at a central location and the different users and programs can then access this data without the need for copying.
Exception Handling: With the class-based exception concept of ABAP, you can define a special control flow for a specific error situation and provide the user with information about the error.
Developing Persistency: For permanent storage of data in ABAP, you use relational database tables by means of database-independent Open SQL, which is integrated in ABAP. However, you can also store selected objects transparently or access the integrated database or other databases using proprietary SQL.
Connectivity and Interoperability: The Exchange Infrastructure and Web services are the means by which developers can implement a service-oriented architecture. With Web services, you can provide and consume services independently of implementation or protocol. Furthermore, you can do so within NetWeaver and in the communication with other systems. With the features of the Exchange Infrastructure, you can enable, manage, and adapt integration scenarios between systems.
Making Enhancements: With the Enhancement Framework, you can enhance programs, function modules, and global classes without modification as well as replace existing code. The Switch Framework enables you activate only specific development objects or enhancements in a system.
Considerable Aspects
It follows a list of aspects to be considered during development. The list of course is not complete.
Dynpro persistence
When implementing dynpros one has to care for himself to read out and persist the necessary fields. Recently it happened to me that I forgot to include a field into the UPDATE-clause which is an error not so easy to uncover if you have other problems to be solved in the same package. Here, tool-support or built-in mechanisms would help.
The developer could help himself out by creating something like a document containing a cookbook or guide in which parts of a dynpro logic one has to care about persistence. With that at hand, it would be quite easy finding those bugs in short time. Maybe a report scanning for the definition of the dynpro fields to be persisted could scan the code automatically, too.
Memory Cache
It should be common-sense that avoiding select-statements onto the database helps reducing the server load. For that the programmer either can resort to function modules if available. This maybe is the case for important tables. Or the programmer needs to implement his own logic using internal tables. Here, the standard software package could provide the developer with a tool or a mechanism auto-generating memory cached tables resp. function modules implementing this.
Sometimes buffering of database tables could be used, if applicable. But that would require an effort in customizing the system and could drain down system performance overall, especially if a table is involved that has a central role.
Interfaces
It should be noticed that some function modules available have an incomplete interface. That means, the interface does not include all parameters evaluated by the logic of the function module. For example, global variables from within the function group could be read out, which cannot be influenced by the general caller. Or memory parameters are used internally to feed the logic with further information.
One workaround here would be copying the relevant parts of the logic to a newly created function module and then adapt it to the own context. This sometimes is possible, maybe if the copied code is not too lengthy and only a few or no calls to other logic is part of it.
A modification of the SAP code could be considered, if the modification itself is unavoidable (or another solution would be not justifiable by estimated effort to spend on it) and if the location of the modification seems quite safe against future upgrades or hot fixes. The latter is something that could be evaluated by contacting the SAP hotline or working with OSS message (searching thru existing one, perhaps open a new one).
Example
'From SAP NetWeaver:'
set an exclusive lock at level object-type & object-id
IF NOT lf_bapi_error = true.
IF ( NOT istourhd-doc_type IS INITIAL ) AND
( NOT istourhd-doc_id IS INITIAL )
CALL FUNCTION 'ENQUEUE_/DSD/E_HH_RAREF'
EXPORTING
obj_typ = istourhd-doc_type
obj_id = istourhd-doc_id
EXCEPTIONS
foreign_lock = 1
system_failure = 2
OTHERS = 3.
IF sy-subrc <> 0.
terminate processing...
lf_bapi_error = true.
...and add message to return table
PERFORM set_msg_to_bapiret2
USING sy-msgid gc_abort sy-msgno
sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4
gc_istourhd gc_enqueue_refdoc space
CHANGING lt_return.
ENDIF.
ENDIF.
ENDIF. " bapi error
Example Report(Type - ALV(Advanced List Viewer))
REPORT Z_ALV_SIMPLE_EXAMPLE_WITH_ITAB .
*Simple example to use ALV and to define the ALV data in an internal
*table
*data definition
tables:
marav. "Table MARA and table MAKT
Data to be displayed in ALV
Using the following syntax, REUSE_ALV_FIELDCATALOG_MERGE can auto-
matically determine the fieldstructure from this source program
Data:
begin of imat occurs 100,
matnr like marav-matnr, "Material number
maktx like marav-maktx, "Material short text
matkl like marav-matkl, "Material group (so you can test to make
" intermediate sums)
ntgew like marav-ntgew, "Net weight, numeric field (so you can test to
"make sums)
gewei like marav-gewei, "weight unit (just to be complete)
end of imat.
Other data needed
field to store report name
data i_repid like sy-repid.
field to check table length
data i_lines like sy-tabix.
Data for ALV display
TYPE-POOLS: SLIS.
data int_fcat type SLIS_T_FIELDCAT_ALV.
select-options:
s_matnr for marav-matnr matchcode object MAT1.
start-of-selection.
read data into table imat
select * from marav
into corresponding fields of table imat
where
matnr in s_matnr.
Check if material was found
clear i_lines.
describe table imat lines i_lines.
if i_lines lt 1.
Using hardcoded write here for easy upload
write: /
'No materials found.'.
exit.
endif.
end-of-selection.
To use ALV, we need a DDIC-structure or a thing called Fieldcatalogue.
The fieldcatalouge can be generated by FUNCTION
'REUSE_ALV_FIELDCATALOG_MERGE' from an internal table from any
report source, including this report.
Store report name
i_repid = sy-repid.
Create Fieldcatalogue from internal table
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
EXPORTING
I_PROGRAM_NAME = i_repid
I_INTERNAL_TABNAME = 'IMAT' "capital letters!
I_INCLNAME = i_repid
CHANGING
CT_FIELDCAT = int_fcat
EXCEPTIONS
INCONSISTENT_INTERFACE = 1
PROGRAM_ERROR = 2
OTHERS = 3.
*explanations:
I_PROGRAM_NAME is the program which calls this function
I_INTERNAL_TABNAME is the name of the internal table which you want
to display in ALV
I_INCLNAME is the ABAP-source where the internal table is defined
(DATA....)
CT_FIELDCAT contains the Fieldcatalouge that we need later for
ALV display
IF SY-SUBRC <> 0.
write: /
'Returncode',
sy-subrc,
'from FUNCTION REUSE_ALV_FIELDCATALOG_MERGE'.
ENDIF.
*This was the fieldcatlogue
Call for ALV list display
CALL FUNCTION 'REUSE_ALV_LIST_DISPLAY'
EXPORTING
I_CALLBACK_PROGRAM = i_repid
IT_FIELDCAT = int_fcat
TABLES
T_OUTTAB = imat
EXCEPTIONS
PROGRAM_ERROR = 1
OTHERS = 2.
*explanations:
I_CALLBACK_PROGRAM is the program which calls this function
IT_FIELDCAT (just made by REUSE_ALV_FIELDCATALOG_MERGE) contains
now the data definition needed for display
I_SAVE allows the user to save his own layouts
T_OUTTAB contains the data to be displayed in ALV
IF SY-SUBRC <> 0.
write: /
'Returncode',
sy-subrc,
'from FUNCTION REUSE_ALV_LIST_DISPLAY'.
ENDIF.
Reward points for useful Answers
Regards
Anji -
Differences between Procedural ABAP and OOPs ABAP
Hi Friends,
Can any one explain the differences between Procedural ABAP and OOPs ABAP in brief ? pls explain the most important ( atleast 3 or 4 points ). pls don't give me any other links, i will appreciate for good responses... and will be awarded with full points...
Thanks and Regards
VijayaHi
Core ABAP (procedural) works with Event driven, subroutine driven one
OOPS ABAP works on the OOPS concepts like Inheritance, polymorphism,abstraction and encapsulation.
see the doc
ABAP is one of many application-specific fourth-generation languages (4GLs) first developed in the 1980s. It was originally the report language for SAP R/2, a platform that enabled large corporations to build mainframe business applications for materials management and financial and management accounting. ABAP used to be an abbreviation of Allgemeiner Berichtsaufbereitungsprozessor, the German meaning of "generic report preparation processor", but was later renamed to Advanced Business Application Programming. ABAP was one of the first languages to include the concept of Logical Databases (LDBs), which provides a high level of abstraction from the basic database level.
The ABAP programming language was originally used by SAP developers to develop the SAP R/3 platform. It was also intended to be used by SAP customers to enhance SAP applications customers can develop custom reports and interfaces with ABAP programming. The language is fairly easy to learn for programmers but it is not a tool for direct use by non-programmers. Good programming skills, including knowledge of relational database design and preferably also of object-oriented concepts, are required to create ABAP programs.
ABAP remains the language for creating programs for the client-server R/3 system, which SAP first released in 1992. As computer hardware evolved through the 1990s, more and more of SAP's applications and systems were written in ABAP. By 2001, all but the most basic functions were written in ABAP. In 1999, SAP released an object-oriented extension to ABAP called ABAP Objects, along with R/3 release 4.6.
SAP's most recent development platform, NetWeaver, supports both ABAP and Java.
Implementation
Where does the ABAP Program Run?
All ABAP programs reside inside the SAP database. They are not stored in separate external files like Java or C++ programs. In the database all ABAP code exists in two forms: source code, which can be viewed and edited with the ABAP workbench, and "compiled" code ("generated" code is the more correct technical term), which is loaded and interpreted by the ABAP runtime system. Code generation happens implicitly when a unit of ABAP code is first invoked. If the source code is changed later or if one of the data objects accessed by the program has changed (e.g. fields were added to a database table), then the code is automatically regenerated.
ABAP programs run in the SAP application server, under control of the runtime system, which is part of the SAP kernel. The runtime system is responsible for processing ABAP statements, controlling the flow logic of screens and responding to events (such as a user clicking on a screen button). A key component of the ABAP runtime system is the Database Interface, which turns database-independent ABAP statements ("Open SQL") into statements understood by the underlying DBMS ("Native SQL"). The database interface handles all the communication with the relational database on behalf of ABAP programs; it also contains extra features such as buffering of frequently accessed data in the local memory of the application server.
Basis
Basis sits between ABAP/4 and Operating system.Basis is like an operating system for R/3. It sits between the ABAP/4 code and the computer's operating system. SAP likes to call it middleware because it sits in the middle, between ABAP/4 and the operating system. Basis sits between ABAP/4 and the operating system. ABAP/4 cannot run directly on an operating system. It requires a set of programs (collectively called Basis) to load, interpret, and buffer its input and output. Basis, in some respects, is like the Windows environment. Windows starts up, and while running it provides an environment in which Windows programs can run. Without Windows, programs written for the Windows environment cannot run. Basis is to ABAP/4 programs as Windows is to Windows programs. Basis provides the runtime environment for ABAP/4 programs. Without Basis, ABAP/4 programs cannot run. When the operator starts up R/3, you can think of him as starting up Basis. Basis is a collection of R/3 system programs that present you with an interface. Using this interface the user can start ABAP/4 programs. To install Basis, an installer runs the program r3inst at the command-prompt level of the operating system. Like most installs, this creates a directory structure and copies a set of executables into it. These executables taken together as a unit form Basis.
To start up the R/3 system, the operator enters the startsap command. The Basis executables start up and stay running, accepting requests from the user to run ABAP/4 programs.
ABAP/4 programs run within the protective Basis environment; they are not executables that run on the operating system. Instead, Basis reads ABAP/4 code and interprets it into operating system instructions. ABAP/4 programs do not access operating system functions directly. Instead, they use Basis functions to perform file I/O and display data in windows. This level of isolation from the operating system enables ABAP/4 programs to be ported without modification to any system that supports R/3. This buffering is built right into the ABAP/4 language itself and is actually totally transparent to the programmer.
Basis makes ABAP/4 programs portable. The platforms that R/3 can run on are shown in Table. For example, if you write an ABAP/4 program on Digital UNIX with an Informix database and an OSF/Motif interface, that same program should run without modification on a Windows NT machine with an Oracle database and a Windows 95 interface. Or, it could run on an AS/400 with a DB2 database using OS/2 as the front-end.
SAP also provides a suite of tools for administering the Basis system. These tools perform tasks such as system performance monitoring, configuration, and system maintenance. To access the Basis administration tools from the main menu, choose the path Tools->Administration.
Platforms and Databases Supported by R/3
Operating Systems Supported Hardware Supported Front-Ends Supported Databases
AIX SINIX IBM SNI SUN Win 3.1/95/NT DB2 for AIX
SOLARIS HP-UX Digital HP OSF/Motif Informix-Online
Digital-UNIX Bull OS/2 Oracle 7.1
Windows NT AT&T Compaq Win 3.1/95/NT Oracle 7.1
Bull/Zenith OSF/Motif SQL Server 6.0
HP (Intel) SNI OS/2 ADABAS D
OS/400 AS/400 Win95 OS/2 DB2/400
SAP Systems and Landscapes
All SAP data exists and all SAP software runs in the context of an SAP system. A system consists of a central relational database and one or more application servers ("instances") accessing the data and programs in this database. A SAP system contains at least one instance but may contain more, mostly for reasons of sizing and performance. In a system with multiple instances, load balancing mechanisms ensure that the load is spread evenly over the available application servers.
Installations of the Web Application Server (landscapes) typically consist of three systems: one for development, one for testing and quality assurance, and one for production. The landscape may contain more systems, e.g. separate systems for unit testing and pre-production testing, or it may contain fewer, e.g. only development and production, without separate QA; nevertheless three is the most common configuration. ABAP programs are created and undergo first testing in the development system. Afterwards they are distributed to the other systems in the landscape. These actions take place under control of the Change and Transport System (CTS), which is responsible for concurrency control (e.g. preventing two developers from changing the same code at the same time), version management and deployment of programs on the QA and production systems.
The Web Application Server consists of three layers: the database layer, the application layer and the presentation layer. These layers may run on the same or on different physical machines. The database layer contains the relational database and the database software. The application layer contains the instance or instances of the system. All application processes, including the business transactions and the ABAP development, run on the application layer. The presentation layer handles the interaction with users of the system. Online access to ABAP application servers can go via a proprietary graphical interface, the SAPGUI, or via a Web browser.
Transactions
We call an execution of an ABAP program using a transaction code a transaction. There are dialog, report, parameter, variant, and as of release 6.10, OO transactions. A transaction is started by entering the transaction code in the input field on the standard toolbar, or by means of the ABAP statements CALL TRANSACTION or LEAVE TO TRANSACTION. Transaction codes can also be linked to screen elements or menu entries. Selecting such an element will start the transaction.
A transaction code is simply a twenty-character name connected with a Dynpro, another transaction code, or, as of release 6.10, a method of an ABAP program. Transaction codes linked with Dynpros are possible for executable programs, module pools, and function groups. Parameter transactions and variant transactions are linked with other transaction codes. Transaction codes that are linked with methods are allowed for all program types that can contain methods. Transaction codes are maintained in transaction SE93.
So, a transaction is nothing more than the SAP way of program executionbut why is it called transaction? ABAP is a language for business applications and the most important features of business applications were and still are are transactions. Since in the early days of SAP, the execution of a program often meant the same thing as carrying out a business transaction, the terms transaction and transaction code were chosen for program execution. But never mix up the technical meaning of a transaction with business transactions. For business transactions, it is the term LUW (Logical Unit of Work) that counts. And during one transaction (program execution), there can be many different LUWs.
Lets have a look at the different kind of transactions:
Dialog Transaction
These are the most common kind of transactions. The transaction code of a dialog transaction is linked to a Dynpro of an ABAP program. When the transaction is called, the respective program is loaded and the Dynpro is called. Therefore, a dialog transaction calls a Dynpro sequence rather than a program. Only during the execution of the Dynpro flow logic are the dialog modules of the ABAP program itself are called. The program flow can differ from execution to execution. You can even assign different dialog transaction codes to one program.
Parameter Transaction
In the definition of a parameter transaction code, a dialog transaction is linked with parameters. When you call a parameter transaction, the input fields of the initial Dynpro screen of the dialog transaction are filled with parameters. The display of the initial screen can be inhibited by specifying all mandatory input fields as parameters of the transaction.
Variant Transaction
In the definition of a variant transaction code, a dialog transaction is linked with a transaction variant. When a variant transaction is accessed, the dialog transaction is called and executed with the transaction variant. In transaction variants, you can assign default values to the input fields on several Dynpro screens in a transaction, change the attributes of screen elements, and hide entire screens. Transaction variants are maintained in transaction SHD0.
Report Transaction
A report transaction is the transaction code wrapping for starting the reporting process. The transaction code of a report transaction must be linked with the selection screen of an executable program. When you execute a report transaction, the runtime environment internally executes the ABAP statement SUBMITmore to come on that.
OO Transaction
A new kind of transaction as of release 6.10. The transaction code of an OO transaction is linked with a method of a local or global class. When the transaction is called, the corresponding program is loaded, for instance methods an object of the class is generated and the method is executed.
Types of ABAP programs
In ABAP, there are two different types of programs:
Report programs(Executable pools)
A Sample ReportReport programs AKA Executable pools follow a relatively simple programming model whereby a user optionally enters a set of parameters (e.g. a selection over a subset of data) and the program then uses the input parameters to produce a report in the form of an interactive list. The output from the report program is interactive because it is not a passive display; instead it enables the user, through ABAP language constructs, to obtain a more detailed view on specific data records via drill-down functions, or to invoke further processing through menu commands, for instance to sort the data in a different way or to filter the data according to selection criteria. This method of presenting reports has great advantages for users who must deal with large quantities of information and must also have the ability to examine this information in highly flexible ways, without being constrained by the rigid formatting or unmanageable size of "listing-like" reports. The ease with which such interactive reports can be developed is one of the most striking features of the ABAP language.
The term "report" is somewhat misleading in the sense that it is also possible to create report programs that modify the data in the underlying database instead of simply reading it.
A customized screen created using Screen Painter,which is one of the tool available in ABAP workbench(T-code = SE51).
Online programs
Online programs (also called module pools) do not produce lists. These programs define more complex patterns of user interaction using a collection of screens. The term screen refers to the actual, physical image that the users sees. Each screen also has a flow logic; this refers to the ABAP code invoked by the screens, i.e. the logic that initializes screens, responds to a users requests and controls the sequence between the screens of a module pool. Each screen has its own Flow Logic, which is divided into a "PBO" (Process Before Output) and "PAI" (Process After Input) section. In SAP documentation the term dynpro (dynamic program) refers to the combination of the screen and its Flow Logic.
Online programs are not invoked directly by their name, but are associated with a transaction code. Users can then invoke them through customizable, role-dependent, transaction menus.
Apart from reports and online programs, it is also possible to develop sharable code units such as class libraries, function libraries and subroutine pools.
Subroutine Pools
Subroutine pools, as the name implies, were created to contain selections of subroutines that can be called externally from other programs. Before release 6.10, this was the only way subroutine pools could be used. But besides subroutines, subroutine pools can also contain local classes and interfaces. As of release 6.10, you can connect transaction codes to methods. Therefore, you can now also call subroutine pools via transaction codes. This is the closest to a Java program you can get in ABAP: a subroutine pool with a class containing a method say main connected to a transaction code!
Type Pools
Type pools are the precursors to general type definitions in the ABAP Dictionary. Before release 4.0, only elementary data types and flat structures could be defined in the ABAP Dictionary. All other types that shouldve been generally available had to be defined with TYPES in type pools. As of release 4.0, type pools were only necessary for constants. As of release 6.40, constants can be declared in the public sections of global classes and type pools can be replaced by global classes.
Class Pools
Class pools serve as containers for exactly one global class. Besides the global class, they can contain global types and local classes/interfaces to be used in the global class. A class pool is loaded into memory by using one of its components. For example, a public method can be called from any ABAP program or via a transaction code connected to the method. You maintain class pools in the class builder.
Interface Pools
Interface pools serve as containers for exactly one global interfacenothing more and nothing less. You use an interface pool by implementing its interface in classes and by creating reference variables with the type of its interface. You maintain interface pools in the class builder.
ABAP Workbench
The ABAP Workbench contains different tools for editing Repository objects. These tools provide you with a wide range of assistance that covers the entire software development cycle. The most important tools for creating and editing Repository objects are:
ABAP Editor for writing and editing program code
ABAP Dictionary for processing database table definitions and retrieving global types
Menu Painter for designing the user interface (menu bar, standard toolbar, application toolbar, function key assignment)
Screen Painter for designing screens (dynamic programs) for user dialogs
Function Builder for displaying and processing function modules (routines with defined interfaces that are available throughout the system)
Class Builder for displaying and processing ABAP Objects classes
The ABAP Dictionary
Enforces data integrity
Manages data definitions without redundancy
Is tightly integrated with the rest of the ABAP/4 Development Workbench.
Enforcing data integrity is the process of ensuring that data entered into the system is logical, complete, and consistent. When data integrity rules are defined in the ABAP/4 Dictionary, the system automatically prevents the entry of invalid data. Defining the data integrity rules at the dictionary level means they only have to be defined once, rather than in each program that accesses that data.
The following are examples of data lacking integrity:
A date field with a month value of 13
An order assigned to a customer number that doesnt exist
An order not assigned to a customer
Managing data definitions without redundancy is the process of linking similar information to the same data definition. For example, a customer database is likely to contain a customers ID number in several places. The ABAP Dictionary provides the capability of defining the characteristics of a customer ID number in only one place. That central definition then can be used for each instance of a customer ID number.
The ABAP Dictionarys integration with the rest of the development environment enables ABAP programs to automatically recognize the names and characteristics of dictionary objects.
Additionally, the system provides easy navigation between development objects and dictionary definitions. For example, as a programmer, you can double-click on the name of a dictionary object in your program code, and the system will take you directly to the definition of that object in the ABAP/4 Dictionary.
When a dictionary object is changed, a program that references the changed object will automatically reference the new version the next time the program runs. Because ABAP is interpreted, it is not necessary to recompile programs that reference changed dictionary objects.
ABAP Syntax
The syntax of the ABAP programming language consists of the following elements:
Statements
An ABAP program consists of individual ABAP statements. Each statement begins with a keyword and ends with a period.
"Hello World" PROGRAM
WRITE 'Hello World'.
This example contains two statements, one on each line. The keywords are PROGRAM and WRITE. The program displays a list on the screen. In this case, the list consists of the line "My First Program".
The keyword determines the category of the statement. For an overview of the different categories, refer to ABAP Statements.
Formatting ABAP Statements
ABAP has no format restrictions. You can enter statements in any format, so a statement can be indented, you can write several statements on one line, or spread a single statement over several lines.
You must separate words within a statement with at least one space. The system also interprets the end of line marker as a space.
The program fragment
PROGRAM TEST.
WRITE 'This is a statement'.
could also be written as follows:
PROGRAM TEST. WRITE 'This is a statement'.
or as follows:
PROGRAM
TEST.
WRITE
'This is a statement'.
Use this free formatting to make your programs easier to understand.
Special Case: Text Literals
Text literals are sequences of alphanumeric characters in the program code that are enclosed in quotation marks. If a text literal in an ABAP statement extends across more than one line, the following difficulties can occur:
All spaces between the quotation marks are interpreted as belonging to the text literal. Letters in text literals in a line that is not concluded with quotation marks are interpreted by the editor as uppercase. If you want to enter text literals that do not fit into a single line, you can use the & character to combine a succession of text literals into a single one.
The program fragment
PROGRAM TEST.
WRITE 'This
is
a statement'.
inserts all spaces between the quotation marks into the literal, and converts the letters to uppercase.
This program fragment
PROGRAM TEST.
WRITE 'This' &
' is ' &
'a statement'.
combines three text literals into one.
Chained Statements
The ABAP programming language allows you to concatenate consecutive statements with an identical first part into a chain statement.
To concatenate a sequence of separate statements, write the identical part only once and place a colon ( after it. After the colon, write the remaining parts of the individual statements, separating them with commas. Ensure that you place a period (.) after the last part to inform the system where the chain ends.
Statement sequence:
WRITE SPFLI-CITYFROM.
WRITE SPFLI-CITYTO.
WRITE SPFLI-AIRPTO.
Chain statement:
WRITE: SPFLI-CITYFROM, SPFLI-CITYTO, SPFLI-AIRPTO.
In the chain, a colon separates the beginning of the statement from the variable parts. After the colon or commas, you can insert any number of spaces.
You could, for example, write the same statement like this:
WRITE: SPFLI-CITYFROM,
SPFLI-CITYTO,
SPFLI-AIRPTO.
In a chain statement, the first part (before the colon) is not limited to the keyword of the statements.
Statement sequence:
SUM = SUM + 1.
SUM = SUM + 2.
SUM = SUM + 3.
SUM = SUM + 4.
Chain statement:
SUM = SUM + : 1, 2, 3, 4.
Comments
Comments are texts that you can write between the statements of your ABAP program to explain their purpose to a reader. Comments are distinguished by the preceding signs * (at the beginning of a line) and " (at any position in a line). If you want the entire line to be a comment, enter an asterisk (*) at the beginning of the line. The system then ignores the entire line when it generates the program. If you want part of a line to be a comment, enter a double quotation mark (") before the comment. The system interprets comments indicated by double quotation marks as spaces.
PROGRAM SAPMTEST *
WRITTEN BY KARL BYTE, 06/27/1995 *
LAST CHANGED BY RITA DIGIT, 10/01/1995 *
TASK: DEMONSTRATION *
PROGRAM SAPMTEST.
DECLARATIONS *
DATA: FLAG " GLOBAL FLAG
NUMBER TYPE I " COUNTER
PROCESSING BLOCKS *
Advantages of ABAP over Contemporary languages
ABAP OBJECTS
Object orientation in ABAP is an extension of the ABAP language that makes available the advantages of object-oriented programming, such as encapsulation, interfaces, and inheritance. This helps to simplify applications and make them more controllable.
ABAP Objects is fully compatible with the existing language, so you can use existing statements and modularization units in programs that use ABAP Objects, and can also use ABAP Objects in existing ABAP programs.
ABAP Statements an Overview
The first element of an ABAP statement is the ABAP keyword. This determines the category of the statement. The different statement categories are as follows:
Declarative Statements
These statements define data types or declare data objects which are used by the other statements in a program or routine. The collected declarative statements in a program or routine make up its declaration part.
Examples of declarative keywords:
TYPES, DATA, TABLES
Modularization Statements
These statements define the processing blocks in an ABAP program.
The modularization keywords can be further divided into:
· Defining keywords
You use statements containing these keywords to define subroutines, function modules, dialog modules and methods. You conclude these processing blocks using the END statements.
Examples of definitive keywords:
METHOD ... ENDMETHOD, FUNCTION ... ENDFUNCTION, MODULE ... ENDMODULE.
· Event keywords
You use statements containing these keywords to define event blocks. There are no special statements to conclude processing blocks - they end when the next processing block is introduced.
Examples of event key words:
AT SELECTION SCREEN, START-OF-SELECTION, AT USER-COMMAND
Control Statements
You use these statements to control the flow of an ABAP program within a processing block according to certain conditions.
Examples of control keywords:
IF, WHILE, CASE
Call Statements
You use these statements to call processing blocks that you have already defined using modularization statements. The blocks you call can either be in the same ABAP program or in a different program.
Examples of call keywords:
CALL METHOD, CALL TRANSACTION, SUBMIT, LEAVE TO
Operational Statements These keywords process the data that you have defined using declarative statements.
Examples of operational keywords:
MOVE, ADD
Unique Concept of Internal Table in ABAP
Internal tables provide a means of taking data from a fixed structure and storing it in working memory in ABAP. The data is stored line by line in memory, and each line has the same structure. In ABAP, internal tables fulfill the function of arrays. Since they are dynamic data objects, they save the programmer the task of dynamic memory management in his or her programs. You should use internal tables whenever you want to process a dataset with a fixed structure within a program. A particularly important use for internal tables is for storing and formatting data from a database table within a program. They are also a good way of including very complicated data structures in an ABAP program.
Like all elements in the ABAP type concept, internal tables can exist both as data types and as data objects A data type is the abstract description of an internal table, either in a program or centrally in the ABAP Dictionary, that you use to create a concrete data object. The data type is also an attribute of an existing data object.
Internal Tables as Data Types
Internal tables and structures are the two structured data types in ABAP. The data type of an internal table is fully specified by its line type, key, and table type.
Line type
The line type of an internal table can be any data type. The data type of an internal table is normally a structure. Each component of the structure is a column in the internal table. However, the line type may also be elementary or another internal table.
Key
The key identifies table rows. There are two kinds of key for internal tables - the standard key and a user-defined key. You can specify whether the key should be UNIQUE or NON-UNIQUE. Internal tables with a unique key cannot contain duplicate entries. The uniqueness depends on the table access method.
If a table has a structured line type, its default key consists of all of its non-numerical columns that are not references or themselves internal tables. If a table has an elementary line type, the default key is the entire line. The default key of an internal table whose line type is an internal table, the default key is empty.
The user-defined key can contain any columns of the internal table that are not references or themselves internal tables. Internal tables with a user-defined key are called key tables. When you define the key, the sequence of the key fields is significant. You should remember this, for example, if you intend to sort the table according to the key.
Table type
The table type determines how ABAP will access individual table entries. Internal tables can be divided into three types:
Standard tables have an internal linear index. From a particular size upwards, the indexes of internal tables are administered as trees. In this case, the index administration overhead increases in logarithmic and not linear relation to the number of lines. The system can access records either by using the table index or the key. The response time for key access is proportional to the number of entries in the table. The key of a standard table is always non-unique. You cannot specify a unique key. This means that standard tables can always be filled very quickly, since the system does not have to check whether there are already existing entries.
Sorted tables are always saved sorted by the key. They also have an internal index. The system can access records either by using the table index or the key. The response time for key access is logarithmically proportional to the number of table entries, since the system uses a binary search. The key of a sorted table can be either unique or non-unique. When you define the table, you must specify whether the key is to be unique or not. Standard tables and sorted tables are known generically as index tables.
Hashed tables have no linear index. You can only access a hashed table using its key. The response time is independent of the number of table entries, and is constant, since the system access the table entries using a hash algorithm. The key of a hashed table must be unique. When you define the table, you must specify the key as UNIQUE.
Generic Internal Tables
Unlike other local data types in programs, you do not have to specify the data type of an internal table fully. Instead, you can specify a generic construction, that is, the key or key and line type of an internal table data type may remain unspecified. You can use generic internal tables to specify the types of field symbols and the interface parameters of procedures . You cannot use them to declare data objects.
Internal Tables as Dynamic Data Objects
Data objects that are defined either with the data type of an internal table, or directly as an internal table, are always fully defined in respect of their line type, key and access method. However, the number of lines is not fixed. Thus internal tables are dynamic data objects, since they can contain any number of lines of a particular type. The only restriction on the number of lines an internal table may contain are the limits of your system installation. The maximum memory that can be occupied by an internal table (including its internal administration) is 2 gigabytes. A more realistic figure is up to 500 megabytes. An additional restriction for hashed tables is that they may not contain more than 2 million entries. The line types of internal tables can be any ABAP data types - elementary, structured, or internal tables. The individual lines of an internal table are called table lines or table entries. Each component of a structured line is called a column in the internal table.
Choosing a Table Type
The table type (and particularly the access method) that you will use depends on how the typical internal table operations will be most frequently executed.
Standard tables
This is the most appropriate type if you are going to address the individual table entries using the index. Index access is the quickest possible access. You should fill a standard table by appending lines (ABAP APPEND statement), and read, modify and delete entries by specifying the index (INDEX option with the relevant ABAP command). The access time for a standard table increases in a linear relationship with the number of table entries. If you need key access, standard tables are particularly useful if you can fill and process the table in separate steps. For example, you could fill the table by appending entries, and then sort it. If you use the binary search option with key access, the response time is logarithmically proportional to the number of table entries.
Sorted tables
This is the most appropriate type if you need a table which is sorted as you fill it. You fill sorted tables using the INSERT statement. Entries are inserted according to the sort sequence defined through the table key. Any illegal entries are recognized as soon as you try to add them to the table. The response time for key access is logarithmically proportional to the number of table entries, since the system always uses a binary search. Sorted tables are particularly useful for partially sequential processing in a LOOP if you specify the beginning of the table key in the WHERE condition.
Hashed tables
This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index. The response time for key access remains constant, regardless of the number of table entries. Like database tables, hashed tables always have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for processing large amounts of data.
Advanced Topics
Batch Input: Concepts
Processing Sessions
The above figure shows how a batch input session works.A batch input session is a set of one or more calls to transactions along with the data to be processed by the transactions. The system normally executes the transactions in a session non-interactively, allowing rapid entry of bulk data into an R/3 System.
A session records transactions and data in a special format that can be interpreted by the R/3 System. When the System reads a session, it uses the data in the session to simulate on-line entry of transactions and data. The System can call transactions and enter data using most of the facilities that are available to interactive users.
For example, the data that a session enters into transaction screens is subject to the same consistency checking as in normal interactive operation. Further, batch input sessions are subject to the user-based authorization checking that is performed by the system.
Advantages of ABAP over Contemporary languages
ABAP Objects offers a number of advantages, even if you want to continue using procedural programming. If you want to use new ABAP features, you have to use object-oriented interfaces anyway.
Sharing Data: With ABAP shared objects, you can aggregate data once at a central location and the different users and programs can then access this data without the need for copying.
Exception Handling: With the class-based exception concept of ABAP, you can define a special control flow for a specific error situation and provide the user with information about the error.
Developing Persistency: For permanent storage of data in ABAP, you use relational database tables by means of database-independent Open SQL, which is integrated in ABAP. However, you can also store selected objects transparently or access the integrated database or other databases using proprietary SQL.
Connectivity and Interoperability: The Exchange Infrastructure and Web services are the means by which developers can implement a service-oriented architecture. With Web services, you can provide and consume services independently of implementation or protocol. Furthermore, you can do so within NetWeaver and in the communication with other systems. With the features of the Exchange Infrastructure, you can enable, manage, and adapt integration scenarios between systems.
Making Enhancements: With the Enhancement Framework, you can enhance programs, function modules, and global classes without modification as well as replace existing code. The Switch Framework enables you activate only specific development objects or enhancements in a system.
Considerable Aspects
It follows a list of aspects to be considered during development. The list of course is not complete.
Dynpro persistence
When implementing dynpros one has to care for himself to read out and persist the necessary fields. Recently it happened to me that I forgot to include a field into the UPDATE-clause which is an error not so easy to uncover if you have other problems to be solved in the same package. Here, tool-support or built-in mechanisms would help.
The developer could help himself out by creating something like a document containing a cookbook or guide in which parts of a dynpro logic one has to care about persistence. With that at hand, it would be quite easy finding those bugs in short time. Maybe a report scanning for the definition of the dynpro fields to be persisted could scan the code automatically, too.
Memory Cache
It should be common-sense that avoiding select-statements onto the database helps reducing the server load. For that the programmer either can resort to function modules if available. This maybe is the case for important tables. Or the programmer needs to implement his own logic using internal tables. Here, the standard software package could provide the developer with a tool or a mechanism auto-generating memory cached tables resp. function modules implementing this.
Sometimes buffering of database tables could be used, if applicable. But that would require an effort in customizing the system and could drain down system performance overall, especially if a table is involved that has a central role.
Interfaces
It should be noticed that some function modules available have an incomplete interface. That means, the interface does not include all parameters evaluated by the logic of the function module. For example, global variables from within the function group could be read out, which cannot be influenced by the general caller. Or memory parameters are used internally to feed the logic with further information.
One workaround here would be copying the relevant parts of the logic to a newly created function module and then adapt it to the own context. This sometimes is possible, maybe if the copied code is not too lengthy and only a few or no calls to other logic is part of it.
A modification of the SAP code could be considered, if the modification itself is unavoidable (or another solution would be not justifiable by estimated effort to spend on it) and if the location of the modification seems quite safe against future upgrades or hot fixes. The latter is something that could be evaluated by contacting the SAP hotline or working with OSS message (searching thru existing one, perhaps open a new one).
Example
'From SAP NetWeaver:'
set an exclusive lock at level object-type & object-id
IF NOT lf_bapi_error = true.
IF ( NOT istourhd-doc_type IS INITIAL ) AND
( NOT istourhd-doc_id IS INITIAL )
CALL FUNCTION 'ENQUEUE_/DSD/E_HH_RAREF'
EXPORTING
obj_typ = istourhd-doc_type
obj_id = istourhd-doc_id
EXCEPTIONS
foreign_lock = 1
system_failure = 2
OTHERS = 3.
IF sy-subrc <> 0.
terminate processing...
lf_bapi_error = true.
...and add message to return table
PERFORM set_msg_to_bapiret2
USING sy-msgid gc_abort sy-msgno
sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4
gc_istourhd gc_enqueue_refdoc space
CHANGING lt_return.
ENDIF.
ENDIF.
ENDIF. " bapi error
Example Report(Type - ALV(Advanced List Viewer))
REPORT Z_ALV_SIMPLE_EXAMPLE_WITH_ITAB .
*Simple example to use ALV and to define the ALV data in an internal
*table
*data definition
tables:
marav. "Table MARA and table MAKT
Data to be displayed in ALV
Using the following syntax, REUSE_ALV_FIELDCATALOG_MERGE can auto-
matically determine the fieldstructure from this source program
Data:
begin of imat occurs 100,
matnr like marav-matnr, "Material number
maktx like marav-maktx, "Material short text
matkl like marav-matkl, "Material group (so you can test to make
" intermediate sums)
ntgew like marav-ntgew, "Net weight, numeric field (so you can test to
"make sums)
gewei like marav-gewei, "weight unit (just to be complete)
end of imat.
Other data needed
field to store report name
data i_repid like sy-repid.
field to check table length
data i_lines like sy-tabix.
Data for ALV display
TYPE-POOLS: SLIS.
data int_fcat type SLIS_T_FIELDCAT_ALV.
select-options:
s_matnr for marav-matnr matchcode object MAT1.
start-of-selection.
read data into table imat
select * from marav
into corresponding fields of table imat
where
matnr in s_matnr.
Check if material was found
clear i_lines.
describe table imat lines i_lines.
if i_lines lt 1.
Using hardcoded write here for easy upload
write: /
'No materials found.'.
exit.
endif.
end-of-selection.
To use ALV, we need a DDIC-structure or a thing called Fieldcatalogue.
The fieldcatalouge can be generated by FUNCTION
'REUSE_ALV_FIELDCATALOG_MERGE' from an internal table from any
report source, including this report.
Store report name
i_repid = sy-repid.
Create Fieldcatalogue from internal table
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
EXPORTING
I_PROGRAM_NAME = i_repid
I_INTERNAL_TABNAME = 'IMAT' "capital letters!
I_INCLNAME = i_repid
CHANGING
CT_FIELDCAT = int_fcat
EXCEPTIONS
INCONSISTENT_INTERFACE = 1
PROGRAM_ERROR = 2
OTHERS = 3.
*explanations:
I_PROGRAM_NAME is the program which calls this function
I_INTERNAL_TABNAME is the name of the internal table which you want
to display in ALV
I_INCLNAME is the ABAP-source where the internal table is defined
(DATA....)
CT_FIELDCAT contains the Fieldcatalouge that we need later for
ALV display
IF SY-SUBRC <> 0.
write: /
'Returncode',
sy-subrc,
'from FUNCTION REUSE_ALV_FIELDCATALOG_MERGE'.
ENDIF.
*This was the fieldcatlogue
Call for ALV list display
CALL FUNCTION 'REUSE_ALV_LIST_DISPLAY'
EXPORTING
I_CALLBACK_PROGRAM = i_repid
IT_FIELDCAT = int_fcat
TABLES
T_OUTTAB = imat
EXCEPTIONS
PROGRAM_ERROR = 1
OTHERS = 2.
*explanations:
I_CALLBACK_PROGRAM is the program which calls this function
IT_FIELDCAT (just made by REUSE_ALV_FIELDCATALOG_MERGE) contains
now the data definition needed for display
I_SAVE allows the user to save his own layouts
T_OUTTAB contains the data to be displayed in ALV
IF SY-SUBRC <> 0.
write: /
'Returncode',
sy-subrc,
'from FUNCTION REUSE_ALV_LIST_DISPLAY'.
ENDIF.
OOPs ABAP uses Classes and Interfaces which uses Methods and events.
If you have Java skills it is advantage for you.
There are Local classes as well as Global Classes.
Local classes we can work in SE38 straight away.
But mostly it is better to use the Global classes.
Global Classes or Interfaces are to be created in SE24.
SAP already given some predefined classes and Interfaces.
This OOPS concepts very useful for writing BADI's also.
So first create a class in SE 24.
Define attributes, Methods for that class.
Define parameters for that Method.
You can define event handlers also to handle the messages.
After creation in each method write the code.
Methods are similar to ABAP PERFORM -FORM statements.
After the creation of CLass and methods come to SE38 and create the program.
In the program create a object type ref to that class and with the help of that Object call the methods of that Class and display the data.
Regards
Anji
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