Updating ztable from the table maintenance

hi,
I want to knw how and where to check , whether the records which user has entered in the table control of new entries screen exists in the ztable table or not . if the same record exists then that record should not go for saving it shd be deleted when it is detected that it exists in the ztable . can any one tell me how . where and what code to be written . so that the duplicate entries are deleted and others entries get appended in the database.
thank you.

Hi
if you have declared some Primary key fields then by default when you enter the records in the Table maintenance using SM30 it will not allow duplicate records with the same key fields
You can check the Table entries in SE16 Tcode
go to Se16 enter table name execute and see the table records
Reward points for useful Answers
Regards
Anji

Similar Messages

Update ztable from internal table

I want to update the Ztable from internal table datas.
what is the syntax to update.
Its urgent send with coding example is better

Hi
PARAMETERS: p_carrid TYPE sflight-carrid,
            percent(1) TYPE p DECIMALS 0.
DATA sflight_tab TYPE TABLE OF sflight.
FIELD-SYMBOLS <sflight> TYPE sflight.
SELECT *
       FROM sflight
       INTO TABLE sflight_tab
       WHERE carrid = p_carrid AND
             fldate = sy-datum.
IF sy-subrc = 0.
LOOP AT sflight_tab ASSIGNING <sflight>.
    <sflight>-price =
      <sflight>-price * ( 1 - percent / 100 ).
ENDLOOP.
ENDIF.
<b>UPDATE sflight FROM TABLE sflight_tab.</b>
Thanks
Vijay
PLZ reward points if helpful

Update ztable from database table directly

hi all,
can u tell me the possible ways to update a ztable from database table directly.
i mean is there anyway to update ztable whenever entry is created in database table .
i dont want to update using insert,modify statements.
points will be rewarded to all hlpful answers.

A slightly dirty solution:
Use SAP functions for reading from CDHEADER and CDPOS tables [with enough filters such that you extract minimum records possible] to read changes to MARA table fields since last run of your program. Use this information to update your ZTABLE. I would recommend having a table maintainance generator on ZTABLE. The actual update should be by a BDC by calling transaction SM30 for ZTABLE maintainance. Now the program may be set up as a batch job running 1ce an hour. You get updates to the extent of 1 hour latency.
Alternatively, you may look if an opportunistic BADI / user Exit is there alongside MM01/02 transactions - assuming the latter are the only ones updating MARA. In this BADI you may write the code to update ZTABLE- again, look to do it by BDC call transaction sm30 to maintain ZTable. To lighten up the code -load on BADI you may simply raise a custom event and move on. You will configure a job that runs your program when that particular event is raised. This will need the 'burden' of figuring out the changes, though.
An elegant way would be to fire a MATMAS fIDOC for every change to Material, capture that and turn back the changes to ZTABLE. This will facilitate the delta load.

Need to update Ztable from final internal table

Hi,
ITAB = Final internal table has 9 fields : 1 2 3 4 5 6 7 8 9
Ztable = Ztable has 6 fields ex : 1 3 4 6 7 8
Structure of both Itab and Ztable are different.
I have data in the Final Internal table and needs to update data into a ztable.
If condition is true...
Modify ztable from itab
endif.
Any suggestions how I can update Ztable from the INternal table
Regards,
Kittu

Hello,
First keep the loop to the final internal table then move all the records to the work area after moving to workarea then create another workarea for the Ztable then move only the field values which are there in Ztable then use modify keyword.
example
move:
y_wa_final_itab-kdauf to y_wa_zhr_item-vbeln,
y_wa_final_itab-kdpos to y_wa_zhr_item-posnr,
y_wa_final_itab-receiptno to y_wa_zhr_item-receiptno
modify zhr_item from y_wa_zhr_item

How to update Ztable from Excel file and how to check conditions ,

HI this uday,
pls help me how can i update Ztable from Excel file and how to check conditions .
regards
uday
Moderator message: please (re)search yourself before asking.
Edited by: Thomas Zloch on Jul 13, 2010 12:00 PM

Hi
Use Fm : ALSM_EXCEL_TO_INTERNAL_TABLE.
L_INTERN : internal table with your fields .
make sure that the fields in the Excel should be formatted (as numeric , characher ) depending upon the data types .
LOOP AT L_INTERN INTO WA_LINTERN .
        MOVE WA_LINTERN-COL TO L_INDEX.
        ASSIGN COMPONENT L_INDEX OF STRUCTURE WA_INREC TO <FS> .
        IF SY-SUBRC = 0.
          MOVE WA_LINTERN-VALUE TO <FS>.
        ENDIF.
        AT END OF ROW .                                    "#EC *
          APPEND WA_INREC TO IT_DATA. "
          CLEAR WA_INREC.
        ENDAT.
     ENDLOOP.
Regards
Swapnil

Update info while using Table Maintenance

Hi All,
I have requirement to update user info and date & time in custom table whoever using Table Maintenance.
ie.
My requirement is if any user updating any table [SAP standard or Custom table] using table maintenance, then
i need to update the user name, date and time into custom table.
Can anbody suggest a solution for this.
Thanks
aRS

Hi,
Try this solution...This might work for custom tables..
Create a new report program..
Take the table name as a parameter..
Then get all the contents from the table and store it in a internal table..
Then call the transaction SM30 with the table name..
Once they update the table and save..The control will come back to the report program...
Then again get the values from the custom table..
Compare the values..If there is any change...Then update your custom table with the user info..
Thanks,
Naren
Message was edited by: Narendran Muthukumaran

How to display the values from the table in the screen

Hi,
I have created a screen where i will enter the values for the field treshold amount and desc and if i press update button .it will update the new values by overriting the existing values .
Now i have got requirement i need to create a button show which will display the existing value from the table. always there will be only one entry...in this table
Please can one give me idea...to do this
or sample code...thanks in advance
regards
paveeeeee

Define a function code 'SHOW' for your button. In your PAI module, when you check for various sy-ucomms, check for 'SHOW' also.
Your code will be like this:
Case sy-ucomm.
when 'SHOW'.
perform show_details.
endcase.
In the perform, you can fetch the data from the table and put it in global variables. In the PBO, move the data from the global variables to the screen fields so that they get displayed on the screen.
Hope this helps. Reward points for useful answers.
Regards
Nithya

How to select the data efficiently from the table

hi every one,
i need some help in selecting data from FAGLFLEXA table.i have to select many amounts from different group of G/L accounts
(groups are predefined here which contains a set of g/L account no.).
if i select every time for each group then it will be a performance issue, in order to avoid it what should i do, can any one suggest me a method or a smaple query so that i can perform the task efficiently.

Hi ,
1.select and keep the data in internal table
2.avoid select inside loop ..endloop.
3.try to use for all entries
check the below details
Hi Praveen,
Performance Notes
1.Keep the Result Set Small
You should aim to keep the result set small. This reduces both the amount of memory used in the database system and the network load when transferring data to the application server. To reduce the size of your result sets, use the WHERE and HAVING clauses.
Using the WHERE Clause
Whenever you access a database table, you should use a WHERE clause in the corresponding Open SQL statement. Even if a program containing a SELECT statement with no WHERE clause performs well in tests, it may slow down rapidly in your production system, where the data volume increases daily. You should only dispense with the WHERE clause in exceptional cases where you really need the entire contents of the database table every time the statement is executed.
When you use the WHERE clause, the database system optimizes the access and only transfers the required data. You should never transfer unwanted data to the application server and then filter it using ABAP statements.
Using the HAVING Clause
After selecting the required lines in the WHERE clause, the system then processes the GROUP BY clause, if one exists, and summarizes the database lines selected. The HAVING clause allows you to restrict the grouped lines, and in particular, the aggregate expressions, by applying further conditions.
Effect
If you use the WHERE and HAVING clauses correctly:
There are no more physical I/Os in the database than necessary
No unwanted data is stored in the database cache (it could otherwise displace data that is actually required)
The CPU usage of the database host is minimize
The network load is reduced, since only the data that is required by the application is transferred to the application server.
Minimize the Amount of Data Transferred
Data is transferred between the database system and the application server in blocks. Each block is up to 32 KB in size (the precise size depends on your network communication hardware). Administration information is transported in the blocks as well as the data.
To minimize the network load, you should transfer as few blocks as possible. Open SQL allows you to do this as follows:
Restrict the Number of Lines
If you only want to read a certain number of lines in a SELECT statement, use the UP TO <n> ROWS addition in the FROM clause. This tells the database system only to transfer <n> lines back to the application server. This is more efficient than transferring more lines than necessary back to the application server and then discarding them in your ABAP program.
If you expect your WHERE clause to return a large number of duplicate entries, you can use the DISTINCT addition in the SELECT clause.
Restrict the Number of Columns
You should only read the columns from a database table that you actually need in the program. To do this, list the columns in the SELECT clause. Note here that the INTO CORRESPONDING FIELDS addition in the INTO clause is only efficient with large volumes of data, otherwise the runtime required to compare the names is too great. For small amounts of data, use a list of variables in the INTO clause.
Do not use * to select all columns unless you really need them. However, if you list individual columns, you may have to adjust the program if the structure of the database table is changed in the ABAP Dictionary. If you specify the database table dynamically, you must always read all of its columns.
Use Aggregate Functions
If you only want to use data for calculations, it is often more efficient to use the aggregate functions of the SELECT clause than to read the individual entries from the database and perform the calculations in the ABAP program.
Aggregate functions allow you to find out the number of values and find the sum, average, minimum, and maximum values.
Following an aggregate expression, only its result is transferred from the database.
Data Transfer when Changing Table Lines
When you use the UPDATE statement to change lines in the table, you should use the WHERE clause to specify the relevant lines, and then SET statements to change only the required columns.
When you use a work area to overwrite table lines, too much data is often transferred. Furthermore, this method requires an extra SELECT statement to fill the work area. Minimize the Number of Data Transfers
In every Open SQL statement, data is transferred between the application server and the database system. Furthermore, the database system has to construct or reopen the appropriate administration data for each database access. You can therefore minimize the load on the network and the database system by minimizing the number of times you access the database.
Multiple Operations Instead of Single Operations
When you change data using INSERT, UPDATE, and DELETE, use internal tables instead of single entries. If you read data using SELECT, it is worth using multiple operations if you want to process the data more than once, other wise, a simple select loop is more efficient.
Avoid Repeated Access
As a rule you should read a given set of data once only in your program, and using a single access. Avoid accessing the same data more than once (for example, SELECT before an UPDATE).
Avoid Nested SELECT Loops
A simple SELECT loop is a single database access whose result is passed to the ABAP program line by line. Nested SELECT loops mean that the number of accesses in the inner loop is multiplied by the number of accesses in the outer loop. You should therefore only use nested SELECT loops if the selection in the outer loop contains very few lines.
However, using combinations of data from different database tables is more the rule than the exception in the relational data model. You can use the following techniques to avoid nested SELECT statements:
ABAP Dictionary Views
You can define joins between database tables statically and systemwide as views in the ABAP Dictionary. ABAP Dictionary views can be used by all ABAP programs. One of their advantages is that fields that are common to both tables (join fields) are only transferred once from the database to the application server.
Views in the ABAP Dictionary are implemented as inner joins. If the inner table contains no lines that correspond to lines in the outer table, no data is transferred. This is not always the desired result. For example, when you read data from a text table, you want to include lines in the selection even if the corresponding text does not exist in the required language. If you want to include all of the data from the outer table, you can program a left outer join in ABAP.
The links between the tables in the view are created and optimized by the database system. Like database tables, you can buffer views on the application server. The same buffering rules apply to views as to tables. In other words, it is most appropriate for views that you use mostly to read data. This reduces the network load and the amount of physical I/O in the database.
Joins in the FROM Clause
You can read data from more than one database table in a single SELECT statement by using inner or left outer joins in the FROM clause.
The disadvantage of using joins is that redundant data is read from the hierarchically-superior table if there is a 1:N relationship between the outer and inner tables. This can considerably increase the amount of data transferred from the database to the application server. Therefore, when you program a join, you should ensure that the SELECT clause contains a list of only the columns that you really need. Furthermore, joins bypass the table buffer and read directly from the database. For this reason, you should use an ABAP Dictionary view instead of a join if you only want to read the data.
The runtime of a join statement is heavily dependent on the database optimizer, especially when it contains more than two database tables. However, joins are nearly always quicker than using nested SELECT statements.
Subqueries in the WHERE and HAVING Clauses
Another way of accessing more than one database table in the same Open SQL statement is to use subqueries in the WHERE or HAVING clause. The data from a subquery is not transferred to the application server. Instead, it is used to evaluate conditions in the database system. This is a simple and effective way of programming complex database operations.
Using Internal Tables
It is also possible to avoid nested SELECT loops by placing the selection from the outer loop in an internal table and then running the inner selection once only using the FOR ALL ENTRIES addition. This technique stems from the time before joins were allowed in the FROM clause. On the other hand, it does prevent redundant data from being transferred from the database.
Using a Cursor to Read Data
A further method is to decouple the INTO clause from the SELECT statement by opening a cursor using OPEN CURSOR and reading data line by line using FETCH NEXT CURSOR. You must open a new cursor for each nested loop. In this case, you must ensure yourself that the correct lines are read from the database tables in the correct order. This usually requires a foreign key relationship between the database tables, and that they are sorted by the foreign key. Minimize the Search Overhead
You minimize the size of the result set by using the WHERE and HAVING clauses. To increase the efficiency of these clauses, you should formulate them to fit with the database table indexes.
Database Indexes
Indexes speed up data selection from the database. They consist of selected fields of a table, of which a copy is then made in sorted order. If you specify the index fields correctly in a condition in the WHERE or HAVING clause, the system only searches part of the index (index range scan).
The primary index is always created automatically in the R/3 System. It consists of the primary key fields of the database table. This means that for each combination of fields in the index, there is a maximum of one line in the table. This kind of index is also known as UNIQUE.
If you cannot use the primary index to determine the result set because, for example, none of the primary index fields occur in the WHERE or HAVING clause, the system searches through the entire table (full table scan). For this case, you can create secondary indexes, which can restrict the number of table entries searched to form the result set.
You specify the fields of secondary indexes using the ABAP Dictionary. You can also determine whether the index is unique or not. However, you should not create secondary indexes to cover all possible combinations of fields.
Only create one if you select data by fields that are not contained in another index, and the performance is very poor. Furthermore, you should only create secondary indexes for database tables from which you mainly read, since indexes have to be updated each time the database table is changed. As a rule, secondary indexes should not contain more than four fields, and you should not have more than five indexes for a single database table.
If a table has more than five indexes, you run the risk of the optimizer choosing the wrong one for a particular operation. For this reason, you should avoid indexes with overlapping contents.
Secondary indexes should contain columns that you use frequently in a selection, and that are as highly selective as possible. The fewer table entries that can be selected by a certain column, the higher that columns selectivity. Place the most selective fields at the beginning of the index. Your secondary index should be so selective that each index entry corresponds to at most five percent of the table entries. If this is not the case, it is not worth creating the index. You should also avoid creating indexes for fields that are not always filled, where their value is initial for most entries in the table.
If all of the columns in the SELECT clause are contained in the index, the system does not have to search the actual table data after reading from the index. If you have a SELECT clause with very few columns, you can improve performance dramatically by including these columns in a secondary index.
Formulating Conditions for Indexes
You should bear in mind the following when formulating conditions for the WHERE and HAVING clauses so that the system can use a database index and does not have to use a full table scan.
Check for Equality and Link Using AND
The database index search is particularly efficient if you check all index fields for equality (= or EQ) and link the expressions using AND.
Use Positive Conditions
The database system only supports queries that describe the result in positive terms, for example, EQ or LIKE. It does not support negative expressions like NE or NOT LIKE.
If possible, avoid using the NOT operator in the WHERE clause, because it is not supported by database indexes; invert the logical expression instead.
Using OR
The optimizer usually stops working when an OR expression occurs in the condition. This means that the columns checked using OR are not included in the index search. An exception to this are OR expressions at the outside of conditions. You should try to reformulate conditions that apply OR expressions to columns relevant to the index, for example, into an IN condition.
Using Part of the Index
If you construct an index from several columns, the system can still use it even if you only specify a few of the columns in a condition. However, in this case, the sequence of the columns in the index is important. A column can only be used in the index search if all of the columns before it in the index definition have also been specified in the condition.
Checking for Null Values
The IS NULL condition can cause problems with indexes. Some database systems do not store null values in the index structure. Consequently, this field cannot be used in the index.
Avoid Complex Conditions
Avoid complex conditions, since the statements have to be broken down into their individual components by the database system.
Reduce the Database Load
Unlike application servers and presentation servers, there is only one database server in your system. You should therefore aim to reduce the database load as much as possible. You can use the following methods:
Buffer Tables on the Application Server
You can considerably reduce the time required to access data by buffering it in the application server table buffer. Reading a single entry from table T001 can take between 8 and 600 milliseconds, while reading it from the table buffer takes 0.2 - 1 milliseconds.
Whether a table can be buffered or not depends its technical attributes in the ABAP Dictionary. There are three buffering types:
Resident buffering (100%) The first time the table is accessed, its entire contents are loaded in the table buffer.
Generic buffering In this case, you need to specify a generic key (some of the key fields) in the technical settings of the table in the ABAP Dictionary. The table contents are then divided into generic areas. When you access data with one of the generic keys, the whole generic area is loaded into the table buffer. Client-specific tables are often buffered generically by client.
Partial buffering (single entry) Only single entries are read from the database and stored in the table buffer.
When you read from buffered tables, the following happens:
1. An ABAP program requests data from a buffered table.
2. The ABAP processor interprets the Open SQL statement. If the table is defined as a buffered table in the ABAP Dictionary, the ABAP processor checks in the local buffer on the application server to see if the table (or part of it) has already been buffered.
3. If the table has not yet been buffered, the request is passed on to the database. If the data exists in the buffer, it is sent to the program.
4. The database server passes the data to the application server, which places it in the table buffer.
5. The data is passed to the program.
When you change a buffered table, the following happens:
1. The database table is changed and the buffer on the application server is updated. The database interface logs the update statement in the table DDLOG. If the system has more than one application server, the buffer on the other servers is not updated at once.
2. All application servers periodically read the contents of table DDLOG, and delete the corresponding contents from their buffers where necessary. The granularity depends on the buffering type. The table buffers in a distributed system are generally synchronized every 60 seconds (parameter: rsdisp/bufreftime).
3. Within this period, users on non-synchronized application servers will read old data. The data is not recognized as obsolete until the next buffer synchronization. The next time it is accessed, it is re-read from the database.
You should buffer the following types of tables:
Tables that are read very frequently
Tables that are changed very infrequently
Relatively small tables (few lines, few columns, or short columns)
Tables where delayed update is acceptable.
Once you have buffered a table, take care not to use any Open SQL statements that bypass the buffer.
The SELECT statement bypasses the buffer when you use any of the following:
The BYPASSING BUFFER addition in the FROM clause
The DISTINCT addition in the SELECT clause
Aggregate expressions in the SELECT clause
Joins in the FROM clause
The IS NULL condition in the WHERE clause
Subqueries in the WHERE clause
The ORDER BY clause
The GROUP BY clause
The FOR UPDATE addition
Furthermore, all Native SQL statements bypass the buffer.
Avoid Reading Data Repeatedly
If you avoid reading the same data repeatedly, you both reduce the number of database accesses and reduce the load on the database. Furthermore, a "dirty read" may occur with database tables other than Oracle. This means that the second time you read data from a database table, it may be different from the data read the first time. To ensure that the data in your program is consistent, you should read it once only and then store it in an internal table.
Sort Data in Your ABAP Programs
The ORDER BY clause in the SELECT statement is not necessarily optimized by the database system or executed with the correct index. This can result in increased runtime costs. You should only use ORDER BY if the database sort uses the same index with which the table is read. To find out which index the system uses, use SQL Trace in the ABAP Workbench Performance Trace. If the indexes are not the same, it is more efficient to read the data into an internal table or extract and sort it in the ABAP program using the SORT statement.
Use Logical Databases
SAP supplies logical databases for all applications. A logical database is an ABAP program that decouples Open SQL statements from application programs. They are optimized for the best possible database performance. However, it is important that you use the right logical database. The hierarchy of the data you want to read must reflect the structure of the logical database, otherwise, they can have a negative effect on performance. For example, if you want to read data from a table right at the bottom of the hierarchy of the logical database, it has to read at least the key fields of all tables above it in the hierarchy. In this case, it is more efficient to use a SELECT statement.
Work Processes
Work processes execute the individual dialog steps in R/3 applications. The next two sections describe firstly the structure of a work process, and secondly the different types of work process in the R/3 System.
Structure of a Work Process
Work processes execute the dialog steps of application programs. They are components of an application server. The following diagram shows the components of a work process:
Each work process contains two software processors and a database interface.
Screen Processor
In R/3 application programming, there is a difference between user interaction and processing logic. From a programming point of view, user interaction is controlled by screens. As well as the actual input mask, a screen also consists of flow logic. The screen flow logic controls a large part of the user interaction. The R/3 Basis system contains a special language for programming screen flow logic. The screen processor executes the screen flow logic. Via the dispatcher, it takes over the responsibility for communication between the work process and the SAPgui, calls modules in the flow logic, and ensures that the field contents are transferred from the screen to the flow logic.
ABAP Processor
The actual processing logic of an application program is written in ABAP - SAPs own programming language. The ABAP processor executes the processing logic of the application program, and communicates with the database interface. The screen processor tells the ABAP processor which module of the screen flow logic should be processed next. The following screen illustrates the interaction between the screen and the ABAP processors when an application program is running.
Database Interface
The database interface provides the following services:
Establishing and terminating connections between the work process and the database.
Access to database tables
Access to R/3 Repository objects (ABAP programs, screens and so on)
Access to catalog information (ABAP Dictionary)
Controlling transactions (commit and rollback handling)
Table buffer administration on the application server.
The following diagram shows the individual components of the database interface:
The diagram shows that there are two different ways of accessing databases: Open SQL and Native SQL.
Open SQL statements are a subset of Standard SQL that is fully integrated in ABAP. They allow you to access data irrespective of the database system that the R/3 installation is using. Open SQL consists of the Data Manipulation Language (DML) part of Standard SQL; in other words, it allows you to read (SELECT) and change (INSERT, UPDATE, DELETE) data. The tasks of the Data Definition Language (DDL) and Data Control Language (DCL) parts of Standard SQL are performed in the R/3 System by the ABAP Dictionary and the authorization system. These provide a unified range of functions, irrespective of database, and also contain functions beyond those offered by the various database systems.
Open SQL also goes beyond Standard SQL to provide statements that, in conjunction with other ABAP constructions, can simplify or speed up database access. It also allows you to buffer certain tables on the application server, saving excessive database access. In this case, the database interface is responsible for comparing the buffer with the database. Buffers are partly stored in the working memory of the current work process, and partly in the shared memory for all work processes on an application server. Where an R/3 System is distributed across more than one application server, the data in the various buffers is synchronized at set intervals by the buffer management. When buffering the database, you must remember that data in the buffer is not always up to date. For this reason, you should only use the buffer for data which does not often change.
Native SQL is only loosely integrated into ABAP, and allows access to all of the functions contained in the programming interface of the respective database system. Unlike Open SQL statements, Native SQL statements are not checked and converted, but instead are sent directly to the database system. Programs that use Native SQL are specific to the database system for which they were written. R/3 applications contain as little Native SQL as possible. In fact, it is only used in a few Basis components (for example, to create or change table definitions in the ABAP Dictionary).
The database-dependent layer in the diagram serves to hide the differences between database systems from the rest of the database interface. You choose the appropriate layer when you install the Basis system. Thanks to the standardization of SQL, the differences in the syntax of statements are very slight. However, the semantics and behavior of the statements have not been fully standardized, and the differences in these areas can be greater. When you use Native SQL, the function of the database-dependent layer is minimal.
Types of Work Process
Although all work processes contain the components described above, they can still be divided into different types. The type of a work process determines the kind of task for which it is responsible in the application server. It does not specify a particular set of technical attributes. The individual tasks are distributed to the work processes by the dispatcher.
Before you start your R/3 System, you determine how many work processes it will have, and what their types will be. The dispatcher starts the work processes and only assigns them tasks that correspond to their type. This means that you can distribute work process types to optimize the use of the resources on your application servers.
The following diagram shows again the structure of an application server, but this time, includes the various possible work process types:
The various work processes are described briefly below. Other parts of this documentation describe the individual components of the application server and the R/3 System in more detail.
Dialog Work Process
Dialog work processes deal with requests from an active user to execute dialog steps.
Update Work Process
Update work processes execute database update requests. Update requests are part of an SAP LUW that bundle the database operations resulting from the dialog in a database LUW for processing in the background.
Background Work Process
Background work processes process programs that can be executed without user interaction (background jobs).
Enqueue Work Process
The enqueue work process administers a lock table in the shared memory area. The lock table contains the logical database locks for the R/3 System and is an important part of the SAP LUW concept. In an R/3 System, you may only have one lock table. You may therefore also only have one application server with enqueue work processes.
Spool Work Process
The spool work process passes sequential datasets to a printer or to optical archiving. Each application server may contain several spool work process.
The services offered by an application server are determined by the types of its work processes. One application server may, of course, have more than one function. For example, it may be both a dialog server and the enqueue server, if it has several dialog work processes and an enqueue work process.
You can use the system administration functions to switch a work process between dialog and background modes while the system is still running. This allows you, for example, to switch an R/3 System between day and night operation, where you have more dialog than background work processes during the day, and the other way around during the night.
ABAP Application Server
R/3 programs run on application servers. They are an important component of the R/3 System. The following sections describe application servers in more detail.
Structure of an ABAP Application Server
The application layer of an R/3 System is made up of the application servers and the message server. Application programs in an R/3 System are run on application servers. The application servers communicate with the presentation components, the database, and also with each other, using the message server.
The following diagram shows the structure of an application server:
The individual components are:
Work Processes
An application server contains work processes, which are components that can run an application. Work processes are components that are able to execute an application (that is, one dialog step each). Each work process is linked to a memory area containing the context of the application being run. The context contains the current data for the application program. This needs to be available in each dialog step. Further information about the different types of work process is contained later on in this documentation.
Dispatcher
Each application server contains a dispatcher. The dispatcher is the link between the work processes and the users logged onto the application server. Its task is to receive requests for dialog steps from the SAP GUI and direct them to a free work process. In the same way, it directs screen output resulting from the dialog step back to the appropriate user.
Gateway
Each application server contains a gateway. This is the interface for the R/3 communication protocols (RFC, CPI/C). It can communicate with other application servers in the same R/3 System, with other R/3 Systems, with R/2 Systems, or with non-SAP systems.
The application server structure as described here aids the performance and scalability of the entire R/3 System. The fixed number of work processes and dispatching of dialog steps leads to optimal memory use, since it means that certain components and the memory areas of a work process are application-independent and reusable. The fact that the individual work processes work independently makes them suitable for a multi-processor architecture. The methods used in the dispatcher to distribute tasks to work processes are discussed more closely in the section Dispatching Dialog Steps.
Shared Memory
All of the work processes on an application server use a common main memory area called shared memory to save contexts or to buffer constant data locally.
The resources that all work processes use (such as programs and table contents) are contained in shared memory. Memory management in the R/3 System ensures that the work processes always address the correct context, that is the data relevant to the current state of the program that is running. A mapping process projects the required context for a dialog step from shared memory into the address of the relevant work process. This reduces the actual copying to a minimum.
Local buffering of data in the shared memory of the application server reduces the number of database reads required. This reduces access times for application programs considerably. For optimal use of the buffer, you can concentrate individual applications (financial accounting, logistics, human resources) into separate application server groups.
Database Connection
When you start up an R/3 System, each application server registers its work processes with the database layer, and receives a single dedicated channel for each. While the system is running, each work process is a user (client) of the database system (server). You cannot change the work process registration while the system is running. Neither can you reassign a database channel from one work process to another. For this reason, a work process can only make database changes within a single database logical unit of work (LUW). A database LUW is an inseparable sequence of database operations. This has important consequences for the programming model explained below.
Dispatching Dialog Steps
The number of users logged onto an application server is often many times greater than the number of available work processes. Furthermore, it is not restricted by the R/3 system architecture. Furthermore, each user can run several applications at once. The dispatcher has the important task of distributing all dialog steps among the work processes on the application server.
The following diagram is an example of how this might happen:
1. The dispatcher receives the request to execute a dialog step from user 1 and directs it to work process 1, which happens to be free. The work process addresses the context of the application program (in shared memory) and executes the dialog step. It then becomes free again.
2. The dispatcher receives the request to execute a dialog step from user 2 and directs it to work process 1, which is now free again. The work process executes the dialog step as in step 1.
3. While work process 1 is still working, the dispatcher receives a further request from user 1 and directs it to work process 2, which is free.
4. After work processes 1 and 2 have finished processing their dialog steps, the dispatcher receives another request from user 1 and directs it to work process 1, which is free again.
5. While work process 1 is still working, the dispatcher receives a further request from user 2 and directs it to work process 2, which is free.
From this example, we can see that:
A dialog step from a program is assigned to a single work process for execution.
The individual dialog steps of a program can be executed on different work processes, and the program context must be addressed for each new work process.
A work process can execute dialog steps of different programs from different users.
The example does not show that the dispatcher tries to distribute the requests to the work processes such that the same work process is used as often as possible for the successive dialog steps in an application. This is useful, since it saves the program context having to be addressed each time a dialog step is executed.
Dispatching and the Programming Model
The separation of application and presentation layer made it necessary to split up application programs into dialog steps. This, and the fact that dialog steps are dispatched to individual work processes, has had important consequences for the programming model.
As mentioned above, a work process can only make database changes within a single database logical unit of work (LUW). A database LUW is an inseparable sequence of database operations. The contents of the database must be consistent at its beginning and end. The beginning and end of a database LUW are defined by a commit command to the database system (database commit). During a database LUW, that is, between two database commits, the database system itself ensures consistency within the database. In other words, it takes over tasks such as locking database entries while they are being edited, or restoring the old data (rollback) if a step terminates in an error.
A typical SAP application program extends over several screens and the corresponding dialog steps. The user requests database changes on the individual screens that should lead to the database being consistent once the screens have all been processed. However, the individual dialog steps run on different work processes, and a single work process can process dialog steps from other applications. It is clear that two or more independent applications whose dialog steps happen to be processed on the same work process cannot be allowed to work with the same database LUW.
Consequently, a work process must open a separate database LUW for each dialog step. The work process sends a commit command (database commit) to the database at the end of each dialog step in which it makes database changes. These commit commands are called implicit database commits, since they are not explicitly written into the application program.
These implicit database commits mean that a database LUW can be kept open for a maximum of one dialog step. This leads to a considerable reduction in database load, serialization, and deadlocks, and enables a large number of users to use the same system.
However, the question now arises of how this method (1 dialog step = 1 database LUW) can be reconciled with the demand to make commits and rollbacks dependent on the logical flow of the application program instead of the technical distribution of dialog steps. Database update requests that depend on one another form logical units in the program that extend over more than one dialog step. The database changes associated with these logical units must be executed together and must also be able to be undone together.
The SAP programming model contains a series of bundling techniques that allow you to group database updates together in logical units. The section of an R/3 application program that bundles a set of logically-associated database operations is called an SAP LUW. Unlike a database LUW, a SAP LUW includes all of the dialog steps in a logical unit, including the database update.
Happy Reading...
shibu

Creating a external content type for Read and Update data from two tables in sqlserver using sharepoint designer

Hi
how to create a external content type for Read and Update data from two tables in sqlserver using sharepoint designer 2010
i created a bcs service using centraladministration site
i have two tables in sqlserver
1)Employee
-empno
-firstname
-lastname
2)EmpDepartment
-empno
-deptno
-location
i want to just create a list to display employee details from two tables
empid firstname deptno location
and same time update in two tables
adil

When I try to create an external content type based on a view (AdventureWorks2012.vSalesPerson) - I can display the data in an external list. When I attempt to edit it, I get an error:
External List fails when attached to a SQL view
Sorry, something went wrong
Failed to update a list item for this external list based on the Entity (External Content Type) 'SalesForce' in EntityNamespace 'http://xxxxxxxx'. Details: The query against the database caused an error.
I can edit the view in SQL Manager, so it seems strange that it fails.
Any advice would be greatly GREATLY appreciated.
Thanks,
Randy

Add authorization checks to the table maintenance

i have created a table maintenance and I have authorization object and the field for it which will take some values this i got from basis people . Then how to add authorization checks to the table maintenance.

U can try to use the event, after generating table maintenance program:
Enviroment->Modification->Events: the events 05/18 could be good for you
Max

Include a field in the table maintenance generator

Hi All,
There is a Z table with MATNR and another numeric field and the table maintenance generator exists for the table. The requirement is to include another field for MAKTX ( Material description) in the table maintenance generator with input disabled. Is it possible to do the same in the table maintenance generator else please suggest me the best solution.
Thanks in Advance.

Hi Srinivasa,
This is quite simple, first add the field MAKTX into the Table and activate it .
Now again generate the Table maintainence for the table.
from Table maintainence generator go to the main program
there click the screen maintained for Table maintainence generator .
in the Pbo of the screen write the following code.
assume table name is table1.
Loop at screen.
if screen-name = table1-maktx.
screen-input = '0'.
modify screen.
endif.
endloop.
this will automatically disable the material description field in the Table Maintainence Generator.
This is will solve your problem
Regards,
Madhavi

To Delete the Entire Data from the Tables

Requirement ::
To use select Options for table name and based on the table names we want to delete the data from the tables...
conditions :
we have to first check if the tables having mandat and the configuration tables if this tables then dnt delete the data from this tables. if the table other than mandat n config tables the data will be deleted from other tables.
Input On Selection Screen :::
Name of the tables : :         we want to select multiple table names using select options.
Type of Update       : :          Synchronous / Asynchronous
Test Run                 : :          /* if test run is selected the tables will be validated based on the condition and the data is not
                                               deleted from the SAP tables or the status is not updated . untill u run Actual run.
Actual Run              : :         /* Here finally the data will be deleted from the SAP tables . the changes finally will be reflected in
                                               Actual run...to the SAP Tables
Output Required :::
srno | Table name   |   No.of Records deleted   |    Date    |    Time
Please provide me the sample code for the above Requirement ...
Thanks in Advance....
Moderator message : Spec dumping is not allowed. Thread locked.
Edited by: Vinod Kumar on Sep 30, 2011 4:54 PM

Venkat,
I belive in LBWQ you can only see one entry for an application. You'll see only one entry MC*18 for all your datasources.
Do one thing. Do not delete from there. Run your "Job Control" job which moves all the data from LBWQ queue to RSA7 queue, making your LBWQ queue empty. Now go to RSA7 and delete your data for the specified datasource...
Been a while since I looked at those screens, but I believe I am right.
Good Luck
Gova

How to remove the approved order from the table in sapui5

Hi Experts,
how to remove the approved order from the table in sapui5.
After Approving the order how to remove the order from the table in sapui5.
Please help me.
Thanks & regards
chitti Babu

Hi,
Probelm is OBIEE on your machine.Some one might have deleted pdf option.
Refer : http://obiee101.blogspot.com/2009/07/obiee-dashboard-default-controls.html
Try to find out tag that is to be removed from controlmessages.xl so that you have only HTML.
Update :
Stop BI Server.Try removing below tag and restart server.
(sawm:if name="enablePDF">(a class="NQWMenuItem" name="pdf" href="javascript:void(null)" onclick="return PortalPrint('@{pdfURL}[javaScriptString]',@{bNewWindow});">
<sawm:messageRef name="kmsgDashboardPrintPDF"/></a)</sawm:if)
Regards,
Srikanth
Edited by: Srikanth Mandadi on Apr 19, 2011 3:36 AM

Incomplete Data on report (report does not show all records from the table)

Hello,
I have problem with CR XI, I'm running the same report on the same data with simple select all records from the table (no sorting, no grouping, no filters)
Sometimes report shows me all records sometimes not. Mostly not all records on the report. When report incomplete sometimes it shows different number of records.
I'm using CR XI runtime on Windows Server 2003
Any help appreciated
Thanks!

Sorry Alexander. I missed the last line where you clearly say it is runtime.
A few more questions:
- Which CR SDK are you using? The Report Designer Component or the CR assemblies for .NET?
- What is the exact version of CR you are using (from help | about)
- What CR Service Pack are you on?
And a troubleshooting suggestion:
Since this works on some machines, it will be a good idea to compare all the runtime (both CR and non CR) being loaded on a working and non working machines.
Download the modules utility from here:
https://smpdl.sap-ag.de/~sapidp/012002523100006252802008E/modules.zip
and follow the steps as described in this thread:
https://forums.sdn.sap.com/click.jspa?searchID=18424085&messageID=6186767
The download also includes instructions on how to use modules.
Ludek

How to get updated values from the loops while they are running

Hello,
I am having difficulty solving a very basic problem, how to access the updated values from the 'FOR loop' while its running? Basically, the VI I am currently working on calls two sub VIs. Each sub VI has a for loop, and both VIs may or may not run for same number of iterations. My goal is to read the values at each terminal inside the loop of both sub VIs, in the Main VI. I tried to achieve it using Global Variables, but in main VI it displays only the last iteration value from both sub VIs. Could anyone please tell me whrere am I going wrong? Is there any other/better way to achieve this.
I appreciate any input on this issue.
Kudos are (always) welcome for the good post. :-)
Solved!
Go to Solution.

Dennis,
In attached VI, I can see the values changing in the sub VI from the main VI with the numeric indicator whose reference is passed on to the sub VI. Now if I wanted to store or use those values how do I do that? I tried to chnge the indicator to control and read from it (in the attached VI) , but the the indicator updates only once. Tried to create a property node and read the Value from it and it didn't work either.
Thanks in Advance!
-Nilesh
Kudos are (always) welcome for the good post. :-)
Attachments:
main-1.vi ‏8 KB
sub-1.vi ‏9 KB

Updating ztable from the table maintenance

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