Difference between sqlplus - start and srvctl start instance
Hello,
why we need to start RAC instances with SRVCTL command, what is the difference between sqlplus -- startup and (srvctl start instance -d dbname -i inst_name)
Thanks
Karthick K
The first ever thing that comes to mind is that sql*plus is not a clusterware utility which means, any updations done from it, may not update correctly the OCR . If you would play with RAC, you may see that doing the startup/shutdown using the sql*plus at times show a conflict the status of the instance when checked through crs_stat command. That's a reason that the srvctl is preferred against sql*plus in the cluster environments.
HTH
Aman....
Similar Messages
-
Difference between list.clear() and new instance
In the below code,
List<String> test = new ArrayList<String)();
list.add("one");
list.add("two");
list.add("three");
list.clear();
(or)
list = new ArrayList<String)();
list.add("four");
list.add("five");
What is the difference between List.clear() and creating new instance for list?1. Use code tags to post codes -- [code]CODE[/code] will display asCODEOr click the CODE button and paste your code between the {code} tags that appear.
2. Invoking clear() sets all the elements of the ArrayList to null and resets the size to 0. public void clear() {
modCount++;
// Let gc do its work
for (int i = 0; i < size; i++)
elementData[i] = null;
size = 0;
}(modCount is used to detect concurrent modification and throw an Exception when needed)
Constructing a new ArrayList creates a new, different, empty ArrayList.
In many situations they might be equivalent, but not in a case where you have two or more variable references to the same ArrayList. Example (watch out for typos)ArrayList<String> stringsA = new ArrayList<String>();
ArrayList<String> stringsB = stringsA;
: // add elements to stringsA
: // stringsB refers to the same populated list
stringsA.clear(); // stringsB refers to the clear()ed list
: // add elements to stringsA again
stringsA = new ArrayList<String>(); // stringsB still refers to the populated listdb -
Difference between a starting date and time and ending date and time
Hi All,
I need to bring out the difference between a starting data and time and ending date and time. Difference should be in time I mean it should be in hours or minus or seconds.
I am sure there must be a Function module for this, Has anyone of you been in search of this kind of FM, Kindly suggest me. It is urgent.
Thanks
MahenHi,
Check this out.
data : date1 type dats , " System data type for Date (sy-datum)
date2 type dats,
time1 type tims, " System data type for time (sy-timlo)
time2 type tims,
days type i,
scd type i,
t_mt type i.
days = date1 - date2. " Diference in days.
Scd = time1 - time2. " diference in seconds.
t_mt = ( days * 24 * 60 ) + ( scd / 60 ).
total diference in minute
<b>Reward Points & Mark Helpful Answers</b> -
Difference between application server and central instance
Hi everyone,
whats the difference between application server and central instance and message server. where it will be installed. and how?
Regards
Basis FresherHi,
just want to clarify that is is not correct that only one enqueue process can be configured on the CI.
Please see the documentation within transaction RZ11 for the parameter Parameter : rdisp/wp_no_enq
Short description : number of enqueue work processes
Parameter description :
You can use this parameter to define the number of enqueue work processes for the instance.
Ensure that a value >0 is only set on the central instance that provides the enqueue server (instance rdisp/enqname ). One enqueue work process on the central instance is normally sufficient (rdisp/wp_no_enq = 1); only in very large systems can a higher value be useful.
Kind Regards
Thomas Alt -
Difference between abap object and function
hi all,
i read the book on abap object of the difference between abap object and classical abap.
i know that there is only 1 instance of a specific function group but somehow i still not so clear why subsequent vehicle cannot use the same function. i also can use the do and loop to call the function? if cannot then why?
hope can get the advice.
thanks
using function *********
function-pool vehicle.
data speed type i value 0.
function accelerate.
speed = speed + 1.
endfunction.
function show_speed.
write speed.
endfunction.
report xx.
start-of-selection.
*vehicle 1
call function 'accelerate'.
call function 'accelerate'.
call function 'show_speed'.
*vehicle 2
*vehicle 3
*****abap object*******
report xx.
data: ov type ref to vehicle,
ov_tab type table of ref to vehicle.
start-of-selection.
do 5 times.
create object ov.
append ov to ov_tab.
enddo.
loop at ov_tab into ov.
do sy-tabix times.
call method ov->accelerate.
enddo.
call method ov->show_speed.
endloop.Hi
Now try this:
REPORT ZTEST_VEHICLEOO .
PARAMETERS: P_CAR TYPE I,
P_READ TYPE I.
* CLASS vehicle DEFINITION
CLASS VEHICLE DEFINITION.
PUBLIC SECTION.
CLASS-DATA: MAX_SPEED TYPE I,
MAX_VEHICLE TYPE I,
NR_VEHICLES TYPE I.
CLASS-METHODS CLASS_CONSTRUCTOR.
METHODS CONSTRUCTOR.
METHODS ACCELERATE.
METHODS SHOW_SPEED.
METHODS GET_SPEED EXPORTING E_SPEED TYPE I.
PRIVATE SECTION.
DATA: SPEED TYPE I,
NR_VEHICLE TYPE I..
ENDCLASS.
* CLASS vehicle IMPLEMENTATION
CLASS VEHICLE IMPLEMENTATION.
METHOD CLASS_CONSTRUCTOR.
NR_VEHICLES = 0.
ENDMETHOD.
METHOD CONSTRUCTOR.
NR_VEHICLES = NR_VEHICLES + 1.
NR_VEHICLE = NR_VEHICLES.
ENDMETHOD.
METHOD ACCELERATE.
SPEED = SPEED + 1.
IF MAX_SPEED < SPEED.
MAX_SPEED = SPEED.
MAX_VEHICLE = NR_VEHICLE.
ENDIF.
ENDMETHOD.
METHOD SHOW_SPEED.
WRITE: / 'Speed of vehicle nr.', NR_VEHICLE, ':', SPEED.
ENDMETHOD.
METHOD GET_SPEED.
E_SPEED = SPEED.
ENDMETHOD.
ENDCLASS.
DATA: OV TYPE REF TO VEHICLE,
OV_TAB TYPE TABLE OF REF TO VEHICLE.
DATA: V_TIMES TYPE I,
FL_ACTION.
DATA: V_SPEED TYPE I.
START-OF-SELECTION.
DO P_CAR TIMES.
CREATE OBJECT OV.
APPEND OV TO OV_TAB.
ENDDO.
LOOP AT OV_TAB INTO OV.
IF FL_ACTION = SPACE.
FL_ACTION = 'X'.
V_TIMES = SY-TABIX * 2.
ELSE.
FL_ACTION = SPACE.
V_TIMES = SY-TABIX - 2.
ENDIF.
DO V_TIMES TIMES.
CALL METHOD OV->ACCELERATE.
ENDDO.
CALL METHOD OV->SHOW_SPEED.
ENDLOOP.
SKIP.
WRITE: / 'Higher speed', VEHICLE=>MAX_SPEED, 'for vehicle nr.',
VEHICLE=>MAX_VEHICLE.
SKIP.
READ TABLE OV_TAB INTO OV INDEX P_READ.
IF SY-SUBRC <> 0.
WRITE: 'No vehicle', P_READ.
ELSE.
CALL METHOD OV->GET_SPEED IMPORTING E_SPEED = V_SPEED.
WRITE: 'Speed of vehicle', P_READ, V_SPEED.
ENDIF.
Try to repeat this using a function group and I think you'll undestand because it'll be very hard to do it.
By only one function group how can u read the data of a certain vehicle?
Yes you can create in the function group an internal table where u store the data of every car: in this way u use the internal table like it was an instance, but you should consider here the example is very simple. Here we have only the speed as characteristic, but really we can have many complex characteristics.
Max -
List of differences between PSE 40 and PSE30
A lot of users are asking what are the differences between PSE 30 and PSE 40.
This Thread provides information on this subject. First, you will find information copied from the section "New Features" of the useful "Adobe Photoshop Elements 4.0 User Guide". Then later on, you might find additional information on the same subject provided by users of PSE.
--- Start of copy of information in the PSE 4.0 User Guide ----
1 What's new in PSE 4.0
1.1 Editing and selection
1.1.1 Magic Selection Brush tool
Easily and accurately select portions of your photos using this new tool in either Standard Edit and Quick Fix. Simply scribble or place dots on the object you want to select -no need to precisely outline the object- and Adobe Photoshop Elements selects the object for you. You can add to or subtract from the selection by using additional tools in the options bar. (See User Guide "To use the Magic Selection Brush tool" on page 193.)
1.1.2 Magic Extractor.
Easily select an object in a photo and extract it from its background. Just scribble or place dots on
the object you want to extract; then scribble or place dots on the background, and Photoshop Elements separates the object from its background. This tool is perfect for creating composites or scrapbook images. (See User Guide "To use the Magic Extractor" on page 194.)
1.1.3 Skin tone adjustment
Click an area of skin and watch the tonal balance of all colors in the photo improve. If you
want, you can also manually adjust the color by using color sliders. (See User Guide "To adjust the color of skin tone" on page 224.)
1.1.4 Red eye removal
Automatically remove red eye during import, or select one or more files and easily remove red eye
in either the Organizer or the Editor. (See User Guide "To remove red eye" on page 249.)
1.1.5 Defringe
Automatically remove the colored specs or halo around the edges of a selection. (See User Guide "To defringe a Selection" on page 200.)
1.1.6 Straighten tool
Straighten and crop crooked photos by drawing a horizontal or vertical line in the image. Photoshop
Elements aligns the photo to that line. (See User Guide "To straighten an image" on page 243.)
1.1.7 WYSIWYG font menu
What you see is what you get -see what each font looks like from within the font menu. (See
User Guide "To choose a font family and style" on page 332.)
1.2 Sharing and printing
1.2.1 One-click printing (US, Canada, Japan only)
Order prints and professional hardbound photo books directly from Photoshop Elements simply by dragging the items to the Order Prints palette. (See User Guide "To use the Order Prints palette (US, Canada, Japan only)" on page 401.)
1.2.2 Slide shows on TV
If you have Windows¨ XP Media Center 2005 installed, you can view your Photoshop Elements
slide shows on your TV and navigate using your TV remote control. (See User Guide "To output a slide show" on page 354.)
1.3 Tagging and organizing
1.3.1 Face tagging
Select a group of photos and let Photoshop Elements isolate and display all the faces so that you can
quickly tag them. The Find Faces dialog box displays thumbnails of each face until you tag it. (See User Guide "To automatically find faces for tagging" on page 101.)
1.3.2 Search by metadata
Search for a variety of metadata criteria, such as file name, file type, shutter speed, camera
model, date, and tags. You can search on multiple criteria at once. (See User Guide "To find photos by details (metadata)" on page 89.)
1.3.3 PDF support
Manage and tag PDF files in the Organizer. PDF files remain intact as one file that you can tag. Open
the PDF in the Editor to extract individual pages. (See User Guide "To open a PDF file" on page 148.)
--- Continuation in next Post of this Thread ------- Continuation from previous Post -----
2 What's changed in PSE 4.0
2.1 Editing and selecting
2.1.1 Crop tool
Freely change image size boundaries while cropping an image. When you're happy with your crop marks,
click the Commit button , which is now conveniently located at the bottom right corner of the crop border. (See User Guide "To crop an image" on page 240.)
2.1.2 Paragraph text
Create paragraph text by dragging a border with the Text tool. The text you enter inside the border
wraps to remain inside the boundaries. (See User Guide "To add text" on page 329.)
2.1.3 Quick Fix
Use the newly enhanced automatic correction options for the most common photo flaws. (See User Guide "To correct color in Quick Fix" on page 207.)
2.1.4 Easier color management
Easily get the color you expect when printing. N ew options and improved embedded
profile support streamline color management. (See User Guide "About color management" on page 236.)
2.1.5 Advanced camera raw
Fine tune exposure and lighting by working with the raw data from your digital camera, and
easily export photos to the universal DNG format. (See User Guide "About camera raw image files" on page 159.)
2.1.6 Artifact reduction
Quickly remove noise caused by shooting in low light or with ISO camera settings by using the
new Remove JPEG Artifacts option in the Noise filter. (See User Guide "Reduce Noise" on page 289.)
2.2 Sharing and printing
2.2.1 Multimedia slide shows
Create feature-rich slide shows with all the new tools and options available in the Slide Show
Editor:
a) Gracefully move from one image to another by adding interesting transitions between each slide. You can choose from over 50 transitions, such as dissolves and doors. (See User Guide "To add and edit transitions" on page 352.)
b) Add text and graphics with the click of a button. (See User Guide "To add text to a slide" on page 348 and "To add clip art graphics to a slide" on page 347.)
c) Make your slide show feel more like a video by panning and zooming your slides. For instance, you can pan from a face on the left side of an image to a face on the right side of the image. (See User Guide "To set pan and zoom" on page 350.)
d) Add background music, make the duration of your slides match the duration of your audio, and narrate your slides all with the click of a button. (See User Guide "To add music to a slide show" on page 347 and "To add narration to a slide" on page 350.)
e) Quickly reorder or edit your slides without leaving the Slide Show Editor. (See User Guide "To reorder slides" on page 346.)
f) Preview anytime by clicking the Preview button, and then output your slide show by burning a DVD (if you have Adobe ' Premiere' Elements installed), sending it in e-mail, sharing it online, or sending it to your TV. (See User Guide "To output a slide show" on page 354.)
2.2.2 Photo mail
Turn plain e-mail into theme-based Photo Mail with enhanced and easier to use captions. (See User Guide "To send a photo using Photo Mail" on page 407.)
2.2.3 Desktop wallpaper
Create original desktop wallpaper using multiple photos. (See User Guide "To use photos as desktop
Wallpaper" on page 367.)
2.2.4 Creations
Create your own cards, calendars, and photo albums, and then print them on your printer, upload them
to the web, or burn them to CD. (See User Guide "About creations" on page 343.)
2.3 Viewing, tagging, and organizing
2.3.1 Faster download
Use the enhanced Photo Downloader to quickly download photos from your digital camera and
mobile phone, even when Photoshop Elements is not running. (See User Guide "To get photos from a digital camera or card reader" on page 62.)
2.3.2 Full Screen and Side By Side View
View your photos in full screen without the clutter of command menus and tools.
(See User Guide "Viewing photos at full screen or side-by-side" on page 76.)
2.3.3 Automatic organization and view options
View your photos as arranged automatically by date, or use the intuitive
Date View or the enhanced Folder Location view. (See User Guide "To sort files in the Photo Browser" on page 71.)
2.3.4 Address book
Import your addresses from Microsoft Outlook address book or vCards. (See User Guide "Using the contact Book" on page 404.)
2.3.5 Captions
Add captions to multiple photos at once. Open and edit audio captions by simply clicking the Audio
icon in thumbnail view in the Photo Browser. (See User Guide "To add captions to files" on page 123 and "To add audio to a photo" on page 124.)
--- End of Information Copied from the Adobe PSE 4.0 User Guide -
Difference between SAP SLD and SAP Management console
Hello,
It seems that both System landscape directory and SAP management console have some overlapping features. The services can be started or stopped in both. Is it true? Does anyone know the difference between these 2 and where does Solution manager fit in?
Thanks
ShailikHi,
SAP SLD is the central information provider in a system landscape.this contains both Component information and Landscape description.COMPONENT Info in sense all the sap products and components along with their versions, And also third party products also.LANDSCAPE desc in sense the description of all the systems in particular landscape.
Example:This can shows exact idea for you.Components like CAF,Webdynpo(WD-java),BPM etc info.And the host names,Message server ports etc.Here we dont have start/stop functionality.
SAP MC provides a common framework for centralized system management. It allows you to monitor and perform basic administration tasks on the SAP system centrally, thus simplifying system administration. Using the SAP MC you can
1.Monitor and control (start, stop, or restart) the SAP system and its instances with a single tool
2.Monitor system alerts
3.Display the list of all access points to an SAP system etc.
We can see difference by looking into http://<host name>:<port>/index.html
Look and feel are also differ.
For more info you can go through these links of sap help.
For SAP SLD:http://help.sap.com/saphelp_nw04/helpdata/en/fe/39ae3d47afd652e10000000a114084/frameset.htm
For SAP MC:http://help.sap.com/saphelp_nwce10/helpdata/en/44/c707c053550f2ce10000000a1553f7/frameset.htm
Thanks,
Murthy. -
Troubleshooting hints - differences between development environment and release environment
Hello,
I am using LabVIEW 8.6 for an application involving stepper motors. We are using 2 Velmex stepper motor systems to run PIR targets for a manufacturing test. The problem I am having is that the program runs fine in the states where it was developed but hangs approximately every 10th run when running in the manufacturing environment in China. Since I am on the EAst coast there is the 12 hour time delay, and I am planning on doing a live support call to find out what is going on. The person who installed the code made some modifications, but I am not aware of the differences. He also may send his code here and see how it runs.
The assumption I am making (based on past experiences from here in the States) is that the stepper motor interface is hanging. since I can't recreate the problem here I can't troubleshoot it.
With a past prooject I was working I did some code on one machine, and when I ran it on a different machine the order of execution for items in a sequence was different between the machines. Has anyone run into this before? Unfortunately for the task at hand the stepper motor has to run at the same time that analog data on multiple channels are being acquired.
Any suggestions?
Mike
MikeThanks for the reply. I did think about putting in a producer-consumer. It turns out that there was a problem with the computer it was being run on. The computer was changed and the problem got better, although it did not go away. The stepper motor was done through a com port talking to another hardware / software solution. The tasks are truly independent and pass no data between them. However, the other task being run involves collecting analog data and updating on a chart (and in one instance stimulating an analog output), and when the stepper motor starts the analog data collection is not updated on the chart. I figure this could be because the charts are a memory hog. No data is lost, and it is running, so I figure if it's not broke don't fix it. It now occasionally locks up. I can run it here for 100 times with zero lock ups, and the last report I got was it ran 30 times in china before locking up. I may have to start examining differences between their machine and my machine.
Now as to the configuration management. It needs to be clarified a wee bit. I'm doing the initial code development / updating, and then we hand off to china, which can make code tweaks as needed. They also have 3 lines running this program, and one of the items I did was to load the differences between lines from configiration files (INI files), and that I got working well. We have fixture variables, items that vary between lines, and configuration items, which are I/O lines and what not. The digital I/O and analog I/O referenced MAX tasks, and that worked well. There are also a com port call for the stepper motor, and in another program an RF power meter, which had to be referenced from an INI file. I will reccomend that they do their code development on one machine and create executables to store on the production lines. We have been bouncing code back and forth from the team members from the states that are currently in china doing the install.
Mike
Mike -
Difference between interface pool and class pool
Hi,
Can any body tell me the difference between Interface pool and Class pool.
thank you in advance.
regardsHi,
Class and Interface Pools
This section discusses the structure and special features of class and interface pools for global classes.
Global Classes and Interfaces
Classes and interfaces are object types. You can define them either globally in the Repository or locally in an ABAP program. If you define classes and interfaces globally, special ABAP programs called class pools or interface pools of type K or J serve as containers for the respective classes and interfaces. Each class or interface pool contains the definition of a single class or interface. The programs are automatically generated by the Class Builder when you create a class or interface.
A class pool is comparable to a module pool or function group. It contains both declarative and executable ABAP statements, but cannot be started on its own. The runtime system can create runtime instances (objects) through a request using the CREATE OBJECT statement. These objects execute the statements of the class pool.
Interface pools do not contain any executable statements. Instead, they are used as containers for interface definitions. When you implement an interface in a class, the interface definition is implicitly included in the class definition.
Structure of a Class Pool
Class pools are structured as follows:
Class pools contain a definition part for type declarations, and the declaration and implementation parts of the class.
Differences From Other ABAP Programs
Class pools are different from other ABAP programs for the following reasons:
· ABAP programs such as executable programs, module pools, or function modules, usually have a declaration part in which the global data for the program is defined. This data is visible in all of the processing blocks in the program. Class pools, on the other hand, have a definition part in which you can define data and object types, but no data objects or field symbols. The types that you define in a class pool are only visible in the implementation part of the global class.
· The only processing blocks that you can use are the declaration part and implementation part of the global class. The implementation part may only implement the methods declared in the global class. You cannot use any of the other ABAP processing blocks (dialog modules, event blocks, subroutines, function modules).
· The processing blocks of class pools are not controlled by the ABAP runtime environment. No events occur, and you cannot call any dialog modules or procedures. Class pools serve exclusively for class programming. You can only access the data and functions of a class using its interface.
· Since events and dialog modules are not permitted in classes, you cannot process screens in classes. You cannot program lists and selection screens in classes, since they cannot react to the appropriate events. It is intended to make screens available in classes. Instead of dialog modules, it will be possible to call methods of the class from the screen flow logic.
Local Classes in Class Pools
The classes and interfaces that you define in the definition part of a class pool are not visible externally. Within the class pool, they have a similar function to local classes and interfaces in other ABAP programs. Local classes can only be instantiated in the methods of the global class. Since subroutines are not allowed in class pools, local classes are the only possible modularization unit in global classes. Local classes have roughly the same function for global classes as subroutines in function groups, but with the significant exception that they are not visible externally
Reward points if useful....
Regards
AK -
Difference between Slave reporsitory and Duplicate repository
Please so kindly, help to explain the following question. Thanks!
1)Why use the port during Repository creation? Is the port connected to XI?
2) Who can explain inside what the difference between Slave reporsitory and Duplicate repository?
Example like below:
When we create a salve repository named "Test002" that was based on repositorty "Test001" (Port:"2345"), after creation, system shows the port for Test 002 is "2035" in Server level, the question is that how the system define the port? Normally, during repository creation, we have to enter a port by manually, but why, when we create a salve repository, system give us the port randomly.
3) The same question like above about repository depulication.Hi Alfred
1. I assume you're referring to the port number for a repository. Some of the MDM utilities connect to a repository which is identified by a port number. This is a TCP port number. Each repository on a server must have a unique port, and they ports should be spaced 5 ports apart (i.e. if repository A uses port 2000, then repository B should use port 2005 - 2001, 2002, 2003 and 2004 can be used by repository A.)
The port is not connected to XI.
2. A slave repository is a <b>read-only</b> point-in-time copy of the master. The slave repository / repositories can be refreshed from the master as required. The slave is aware of who its master is. The master-slave scenario is utilised to create redundancy.
A duplicated repository is simply a copy of a repository. It is not read-only, and has no link to it's "source" repository.
Port numbers for new repositories are not random - they are calculated, starting from 2000 in increments of 5.
3. Neither creating a slave nor creating a duplicate repository asks for a port number. The number used in both instances is calculated.
HTH
Mark -
Difference between Window Subwindow and Mainwindow
Hi I am new to smartforms. I want to know Difference between Window Subwindow and Mainwindow. are all these same ? Can i create a subwindow inside a main window ?
Hi
see the different types of Windows
What are the different types of windows in SAP Scripts?
Windows are defined in the Layout sets which define the position and the text to displayed.
The different types of windows are:
MAIN - Main Window
The main window is a continous window which can extend over several pages. If the text in the main window fills up a page, a new page is created.
Only one main window can be defined in the SAP Script whereas upto 100 instances of main window can be created in a page.
VAR - Variable Window
This window can have the variable contents displayed on them. The contents of the window cannot exceed the window size. The content can be formatted for each page.
CONST - Constant Window
The constant window can have a fixed content and is formatted only once.
Main Windows (MAIN)
Each form must have one window of type MAIN. Such a window is called the main window of the form. For SAPscript forms, the main window has a central meaning:
It controls the page break.
It contains the text body that may cover several pages.
It allows to fix text elements at the upper and lower margins of the allocated page window (for example, for column headings).
As soon as a window of type MAIN is full, SAPscript automatically triggers a page break and continues to output the remaining text in the main window of the subsequent page. Page windows of type MAIN have the same width throughout the form. The SAPscript composer thus avoids reformatting of the text after each page break.
Variable Windows (VAR)
The contents of variable windows is processed again for each page, on which the window appears. The system outputs only as much text as fits into the window. Text exceeding the window size is truncated; the system does not trigger a page break. Unlike constant windows, the page windows declared as variable windows may have different sizes on different form pages.
Constant Windows (CONST)
Starting with Release 4.0, the system internally processes windows of type CONST similar to windows of type VAR. Therefore, if you create a new window, always use type VAR.
Regards
ANJI -
Difference between Data-centric and Document-centric use
Hi,
Can someone suggest what exactly is the difference between Data-centric and Document-centric use and examples if any.
Thanks in advance.
ChaitanyaMaybe it helps if you look at it this way...
Document centric: document centric use of xml data is data that you always use in its complete form. If you want to use the data, then you always will retrieve it as one entity or you save it as one entity. You are not interested in the xml data / information inside this "package" / document, you are only interested in its total form. Lets say, you have an invoice which can be printed on one sheet of paper. This paper that contains you data, will always be treated in a document driven way, that is, in its total representation: information containted on a sheet of paper (document).
Data centric. data centric use of xml, is usage of data were the main interest point is focused on only pieces of the total set of xml data within a document. So instead of being interested in the whole invoice, you only are interested in information like "amount of money to be payed" or "invoicenumber".
Handling of XML data comes with (hidden) costs. Knowing how your data will be used, has to be used, is one of the first steps in designing you environment (and will have an big impact if you choose poorly). For instance, if you know that your data will always be handled (and must be stored) in a document driven way, then it will make sense to store it based on CLOB based XMLType storage. This will garantee best performance retrieval for your xml document. If you now that your xml data has to be stored so that it can be handled in a data centric way, then Object Relational XMLType storage. If conditions are setup properly data retrieval, inserts and updates will be more cost efficient then when based on CLOB XMLType storage.
There are more differences and "cost markers" when or when not to use CLOB, OR or for instance Binary XML. The first two chapters of the XMLDB Developers Guide for Oracle 11g will give you a good head start making some of those decisions. Be also aware that you probably will have to make compromises. The current state of XML, for example, doesn't have the final solution yet for a uniform storage method.
Message was edited by:
Marco Gralike -
Wat is the exact differences between clustered table and pooled table
hi,
can you tell me ravi...wat is the exact differences between clustered table and pooled table
with regards//
anilreddygHi Anil Reddy
Pooled Tables, Table Pools, Cluster Tables, and Table Clusters
These types of tables are not transparent in the sense that they are not legible or manageable directly using the underlying database system tools. They are managed from within the R/3 environment from the ABAP dictionary and also at runtime when they are loaded into application memory.Pool and cluster tables are logical tables. Physically, these logical tables are arranged as records of transparent tables. The pool and cluster tables are grouped together in other tables, which are of the transparent type. The tables that group together pool tables are known as table pools, or just pools; similarly, table clusters, or just
clusters, are the tables which group cluster tables.Not all operations that can be performed over transparent tables can be executed over pool or cluster tables.
For instance, you can manage these tables using Open SQL calls from ABAP, but not Native SQL.These tables are meant to be buffered and loaded in memory, because they are commonly used for storing internal control information and other types of data with no external (business) relevance. SAP recommends that tables of pool or cluster type be used exclusively for control information such as
program parameters, documentation, and so on. Transaction and application data should be stored in transparent tables.
Table Pools
From the point of view of the underlying DBMS as from the point of view of the ABAP dictionary, a table pool is a transparent table containing a group of pooled tables which, when created, were assigned to this table pool.
Field Type Description
TABNAME CHAR(10) Table name
VARKEY CHAR(n) Maximum key length n =< 110
DATALN INT2(5) Length of the VARDATA record returned
VARDATA RAW(m) Maximum length of the data varies according to DBMS
Table Clusters
Similarly to pooled tables, cluster tables are logical tables which, when created, are assigned to a table cluster. Therefore, a table cluster, or just cluster, groups together several tables of type clusters.Several logical rows from different cluster tables are brought together in a single physical record. The records
from the cluster tables assigned to a cluster are thus stored in a single common table in the database.A cluster contains a transparent cluster key which must be located at the start of the key of all logical cluster tables to be included in the cluster. As well, a cluster contains a long field (VARDATA), which contains the
data of the cluster tables for this key. If the data does not fit into a field, continuation records are created.
Field Type Description
CLKEY1 CHAR(*) First key fields
CLKEY2 CHAR(*) Second key field
CLKEYN CHAR(*) nth key field
PAGENO INT2(5) Number of the next page
TIMESTMP CHAR(14) Time stamp
PAGELG INT2(5) Length of the VARDATA record returned
VARDATA RAW(*) Maximum length of the data section; varies according to database system
Working with Tables
The dictionary includes many functions for working with tables. There are five basic operations you can perform on tables: display, create, delete, modify, copy. Please do not confuse displaying a table with displaying the table entries (table contents). In order to display a table, it must previously exist; otherwise the system will display an error message in the status bar. For the following example, the table TABNA is used. To display this table, from the main dictionary screen, enter the table name in the Object name
input field with the radio button selected next to Tables. Then, click on the Display button at the bottom of the screen, or press the F7 function key, or, alternatively,
select Dictionary object Display from the menu.
In this screen, you can see table information such as
¨ Table type, shown next to the name of the object. In the example, it is a transparent table.
¨ Short text description.
¨ Name of the user who made the last change, and the date of the change.
¨ Master language.
¨ Table status. On the screen, you can see this table is saved and active.
¨ Development class. For information on development classes, refer to Chap. 6.
Delivery class, which sets the maintenance group for the table. It controls how tables will behave during client copy procedures, upgrades, and so forth.¨
Tab. Maint. Allowed flag, which indicates whether you can generate a screen for maintaining table entries.
¨Then, on the lower part of the screen, you can see the table fields with all associated characteristics such as:
¨ Field name.
¨ Key indicator. When set, this field is the primary key, or part of it.
¨ Data element.
¨ Basic data type.
¨ Length.
¨ Check table.
¨ Short text, describing the field.
Additional information about the table can be displayed by selecting the corresponding functions from the menu or directly from the application toolbar, such as keys, indexes, or technical settings
Standard table:
The key access to a standard table uses a sequential search. The time required for an access is linearly dependent on the number of entries in the internal table.
You should usually access a standard table with index operations.
Sorted table:
The table is always stored internally sorted by its key. Key access to a sorted table can therefore use a binary search. If the key is not unique, the entry with the lowest index is accessed. The time required for an access is logarithmically dependent on the number of entries in the internal table.
Index accesses to sorted tables are also allowed. You should usually access a sorted table using its key.
Hash table:
The table is internally managed with a hash procedure. All the entries must have a unique key. The time required for a key access is constant, that is it does not depend on the number of entries in the internal table.
You cannot access a hash table with an index. Accesses must use generic key operations (SORT, LOOP, etc.).
Index table:
The table can be a standard table or a sorted table.
Index access is allowed to such an index table. Index tables can be used to define the type of generic parameters of a FORM (subroutine) or a function module.
Just have a look at these links:
http://help.sap.com/saphelp_nw04/helpdata/en/90/8d7304b1af11d194f600a0c929b3c3/frameset.htm
http://help.sap.com/saphelp_nw04/helpdata/en/74/83015785d811d295a800a0c929b3c3/frameset.htm
Regards
Sreeni -
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 -
The difference between system restore and last good known configuration
hi,
what is the difference between system restore and last good known configuration.
in which situation you use system restore ,and in which situation you use last good known configuration.
very short answer wil be enough.
thanks
johan
h.davidLast Known Good Configuration deals only with Starting Windows eg. a bad registry or incorrect driver is preventing Windows to start.It recovers the registry settings of HKEY_LOCAL_MACHINE\System\CurrentControlSet
While System Restore uses restore points to return your system files and settings to an earlier point in time without affecting personal files. Restore points are created automatically every week, and just before significant system events, such as the installation
of a program or device driver. You can also create a restore point manually.You can undone system restore but there is no such option in Last Known Good Configuration.
Last Known Good Configuration is disabled in Windows 8 or,Windows 8.1 by default.
Try using Last Known Good Configuration if you can't start Windows, but it started correctly the last time you turned on the computer.
Try using System Restore to return the system to an earlier point in time when things worked correctly.
S.Sengupta, Windows Entertainment and Connected Home MVP
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