METHOD OF DOING BATCH DATA COMMUNICATION
BDC is used to transfer data from SAP to SAP system or from a non-SAP system to SAP system.
It uses the normal Transaction codes to transfer the data.
This method is used to transfer large amount data that is available in electronic form.
1. CLASSICAL METHOD (CREATING BATCH INPUT SESSION)
This is the standard method to do a BDC.
It offers management of sessions, support for playing back and
correcting sessions that contain errors, and detailed logging.
BDC program will read the data from a sequential dataset file is
stored in a batch-input session.
A session is a collection of transaction data for one or more
transactions.
To run the transactions in the session, you need to execute the
session. You can start and monitor the session from System =>
Services => Batch Input(see screenshot procedure)
The batch-input program must not open a session until it has
closed the preceding session, So you must close it after
transferring data.
You may also process Batch input session using background
processing system.
This method uses the function module BDC OPEN, BDC INSERT
and BDC CLOSE to generate the sessions
2. CALL TRANSACTION :
Run BDC using CALL TRANSACTION does not create a session. The playback, interactive correction, and logging facilities offered
for batch input sessions that are not available for CALL
TRANSACTION.
This method offers faster processing of data than batch input
sessions.
It is recommended that if you're having problems getting data
entered into your SAP System quickly enough.
Your program prepares the data and calls the desired transaction
for immediate processing.
The most important aspects of CALL TRANSACTION interface are:
- Synchronous processing
- Transfers data for a single transaction
- Synchronous and asynchronous database updating both
possible
The program specifies which kind of updating is desired.
Separate LUW for the transaction
The system performs a database commit immediately before
and after the CALL TRANSACTION USING statement.
Both Batch Input Session & Call Transaction methods above need a common data structure for storing the instructions and data for SAP transactions.
To transfer data from an SAP system to another SAP system you may use RFC or CPI-C.
The data transfer program should convert the data that has to transfer into the SAP system as required by the SAP data structure or the transactions using it.
A conversion of the data types could be necessary at times.
In case of data type mismatch, convert the data types to type C.
And this data transfer program should be able to export the data in SAP format to a sequential file.
The BDC program reads the data from this file during the upload of the data into the SAP system
3. CALL DIALOG :
This method is not recommended to be used to do a BDC if you
can enter data by way of sessions or CALL TRANSACTION USING.
In this method, your program prepares data for a sequence of
dialog screens, and calls a dialog module for immediate
processing.
The most important aspects of the CALL DIALOG interface are: -
Synchronous processing
- Transfers data for a sequence of dialog screens
- No separate database update for the dialog
A database update occurs only when the calling program
executes
a commit operation. - Shares LUW with calling program
- No batch input processing log is generated
The data and the necessary action to be performed in order to enter the data into the SAP is stored in Batch Input data structure (BDCDATA).
This structure is used in all the three methods mentioned above
