Programming Guide - Actian

Handling Database ErrorsThe if statement in the example calls the error-handling procedure. Thisprocedure first checks to see if there was a DBMS error. If none occurred, itreturns ER_OK to the calling program. If an error occurred and the error wasnot a deadlock error, then the routine displays an error message that includesthe generic and local DBMS error number. If the error was a deadlock, theprocedure sends an event back to the application to retry the DBMS statement.The following code is the error handling procedure:/*** Name: error_handler -- Detects and handles DBMS** errors.**** Description:** This procedure first checks if an error occurred** in the previous DBMS statement. If so, it pops up** an error message. If the error was deadlock or** another error for which retry is appropriate, it** sends an event back to the calling** frame to retry the DBMS statement.** No need to roll back the transaction in either** case because the main_control frame set the** application's database session to roll back** automatically for all DBMS errors.**** Called By:** check_out frame.**** Parameters:** frm Frame which called this procedure.** commit_evt Event sent to calling frame when** there is a deadlock to retry DBMS** statements.**** Returns:** DBSession.ErrorNumber set by previous DBMS** statement;** ER_OK (0) if success*/procedure error_handler(frm = FrameExec, /* Calling frame */commit_evt = varchar(32), /* Commit event for** retries if** a deadlock** occurred. */) =declareerr_no = integer not null /* Error number */enddeclareWorking with a Database 203