BDC

Q) What is BDC? What's its use?

BDCs are used for transferring of large/external/legacy data into SAP system using Batch Input programming. Batch input is a automaticprocedure referred to as BDC(Batch Data Communications).The centralcomponent of the transfer is a queue file which receives the data vie a batch inputprograms and groups associated data into "sessions".

Q) What is the approach to write a BDC program?
Q) What are the types of BDCs?

1. Call Transaction Method
2. Session Method
3. Direct Input method

Q) What is BDC recording?

BDC works on the principle of simulating user input for transactional screen, via an ABAP program. A BDC recording records the transaction through which data is to be uploaded. This tool will create a program to populate various fields in a transaction. Both call transaction and session method programs can be coded using this tool .

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

Session method uses 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.

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 -In this method, we use CALL TRANSACTION USING to run an SAP transaction. Synchronous and asynchronous database updating both possible The program specifies which kind of updating is desired. The system performs a database commit immediately before and after the CALL TRANSACTION USING statement. No batch input processing log is generated.

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

Q) How did you handle errors in Call Transaction?

We can create a internal table like 'bsgmcgcoll'. All the messages will go to internal table. We can get errors in this internal table.
Below messages are go to internal table. when you run the call transaction.

• Message type
• Message id
• Message Number
• Variable1
• Variable2
• Variable3

Q) What is the role of BDCdata in call transaction method?

in bdc you need to pass data to particular screen and particular screenfields.We do this using thestructure BDCDATA available in the abap dictonary. for moreinformation just have a look at asample code for BDC.

Q) What is bdcmsgcol and how it works with call transaction method?

BDCMSGCOLL is a structure available in the abap dictonary. We use thisto handle errors in calltransaction. We need to declare an internal table like bdcmsgcoll.When a database table is updated we get some messages like sucessfull , ornot sucessfull or sucessful with some warning message. All these messages5pass through this structure. We can capture them using a function modulecalled FORMAT_MESSAGE.