BDC?

[rcvalluri]

hi!

I was asked in an interview recently, why I have chosen BDC session method for data transfer.

Can any body tell why we go for recording when there are other methods like direct input,LSMW,BAPI.

and also if we select recording method for example,when should we use 'call transaction' or 'session method'

any realtime guys please help me!

[Former Member]

We go for call transaction when the number of records to be processed is less than about 10000 and session method when the number of records is more than 10000.

[Former Member]

<b>Batch input</b> is a two-step procedure. It involves a program that creates the batch input session. This session is the data file that includes everything to begin the transaction and the data to be entered on the appropriate screens. The data is not yet in the database tables of R/3 application. The second step is to process the session, which then actually transfers the data to database table. You can transfer data directly to database table by using CALL TRANSACTION method also. <b>Another method - Direct Input, is done for high volume of data for the standard application</b>.

<b>BATCH DATA COMMUNICATION</b>

About Data Transfer In R/3 System

When a company decides to implement the SAP R/3 to manage business-critical data, it usually does not start from a no-data situation. Normally, a SAP R/3 project comes into replace or complement existing application.

In the process of replacing current applications and transferring application data, two situations might occur:

• The first is when application data to be replaced is transferred at once, and only once.

• The second situation is to transfer data periodically from external systems to SAP and vice versa.

• There is a period of time when information has to be transferred from existing application, to SAP R/3, and often this process will be repetitive.

The SAP system offers two primary methods for transferring data into SAP systems. From non-SAP systems or legacy system. These two methods are collectively called “batch input” or “batch data communication”.

1. SESSION METHOD

2. CALL TRANSACTION

3. DIRECT INPUT

<b>Advantages offered by BATCH INPUT method:</b>

1. Can process large data volumes in batch.

2. Can be planned and submitted in the background.

3. No manual interaction is required when data is transferred.

4. Data integrity is maintained as whatever data is transferred to the table is through transaction. Hence batch input data is submitted to all the checks and validations.

[Former Member]

Difference Between Batch Input and Call Transaction in BDC

What is the difference between batch input and call transaction in BDC?

Session method.

1) synchronous processing.

2) can tranfer large amount of data.

3) processing is slower.

4) error log is created

5) data is not updated until session is processed.

Call transaction.

1) asynchronous processing

2) can transfer small amount of data

3) processing is faster.

4) errors need to be handled explicitly

5) data is updated automatically

Batch Data Communication (BDC) is the oldest batch interfacing technique that SAP provided since the early versions of R/3. BDC is not a typical integration tool, in the sense that, it can be only be used for uploading data into R/3 and so it is

not bi-directional.

BDC works on the principle of simulating user input for transactional screen, via an ABAP program.

Typically the input comes in the form of a flat file. The ABAP program reads this file and formats the input data screen by screen into an internal table (BDCDATA). The transaction is then started using this internal table as the input and executed in the background.

In ‘Call Transaction’, the transactions are triggered at the time of processing itself and so the ABAP program must do the error handling. It can also be used for real-time interfaces and custom error handling & logging features. Whereas in

Batch Input Sessions, the ABAP program creates a session with all the transactional data, and this session can be viewed, scheduled and processed (using Transaction SM35) at a later time. The latter technique has a built-in error processing mechanism too.

Batch Input (BI) programs still use the classical BDC approach but doesn’t require an ABAP program to be written to format the BDCDATA. The user has to format the data using predefined structures and store it in a flat file. The BI program then reads this and invokes the transaction mentioned in the header record of the file.

Direct Input (DI) programs work exactly similar to BI programs. But the only difference is, instead of processing screens they validate fields and directly load the data into tables using standard function modules. For this reason, DI programs are much faster (RMDATIND - Material Master DI program works at least 5 times faster) than the BDC counterpart and so ideally suited for loading large volume data. DI programs are not available for all application areas.

Cheers

VJ

If it helps mark points

[Former Member]

hi Nani,

Check out these ..

What are session method and call transaction method and explain about them?

Ans Session method – Use the BDC_OPEN_GROUP to create a session. Once we have created a session, then we can insert the batch input data into it with BDC_INSERT. Use the BDC_INSERT to add a transaction to a batch input session. We specify the transaction that is to be started in the call to BDC_INSERT. We must provide a BDCDATA structure that contains all the data required to process the transaction completely. Use the BDC_CLOSE_GROUP to close a session after we have inserted all of our batch input data into it. Once a session is closed, it can be processed.

Call Transaction -

In this method, we use CALL TRANSACTION USING to run an SAP transaction. External data does not have to be deposited in a session for later processing. Instead, the entire batch input process takes place inline in our program.

If you have 10000 records in your file, which method you use in BDC?

Ans Call transaction is faster then session method. But usually we use session method in real time...because we can transfer large amount of data from internal table to database and if any errors in a session, then process will not complete until session get correct.

Regards,

Santosh