isCOBOL DatabaseBridge : Transactions
Transactions
A transaction means a sequence of information exchange and related work (such as database updating) that is treated as a unit for the purposes of satisfying a request and for ensuring database integrity. For a transaction to be completed and database changes to made permanent, a transaction has to be completed in its entirety. If something happens before the transaction is successfully completed, any changes to the database must be kept track of so that they can be undone.
In order to manage transactions, the connection to the database must not be in autocommit mode, therefore the following setting should appear in the runtime configuration when the connection to the database is established:
iscobol.jdbc.autocommit=false
In this way, every modification to the database data is done within a transaction. When every modification has been done, the program can confirm (COMMIT) or cancel (ROLLBACK) and the database will be updated accordingly.
In order to confirm the data modification, your program should call the EDBI_COMMIT routine:
CALL "EDBI_COMMIT" USING RET-CODE, RET-ERMC.
In order to cancel the data modification, your program should call the EDBI_ROLLBACK routine:
CALL "EDBI_ROLLBACK" USING RET-CODE, RET-ERMC.
RET-CODE and RET-ERMC should be defined as follows:
01 RET-CODE  PIC S9(10).
01 RET-ERMC  PIC X(256).
They receive the SQL return code (0 if successful, non-zero if an error occurred) and the error description respectively.
In this scenario you can also instruct the DatabaseBridge to automatically issue a COMMIT after n operations. See -cc option for details.