ASA SQL User's Guide
  Using Procedures, Triggers, and Batches

Errors and warnings in procedures and triggers

After an application program executes a SQL statement, it can examine a status code. This status code (or return code) indicates whether the statement executed successfully or failed and gives the reason for the failure. You can use the same mechanism to indicate the success or failure of a CALL statement to a procedure.

Error reporting uses either the SQLCODE or SQLSTATE status descriptions. For full descriptions of SQLCODE and SQLSTATE error and warning values and their meanings, see Database Error Messages. Whenever a SQL statement executes, a value appears in special procedure variables called SQLSTATE and SQLCODE. That value indicates whether or not there were any unusual conditions encountered while the statement was being performed. You can check the value of SQLSTATE or SQLCODE in an IF statement following a SQL statement, and take actions depending on whether the statement succeeded or failed.

For example, the SQLSTATE variable can be used to indicate if a row is successfully fetched. The TopCustomerValue procedure presented in section Using cursors on SELECT statements in procedures used the SQLSTATE test to detect that all rows of a SELECT statement had been processed.

Default error handling in procedures and triggers
Error handling with ON EXCEPTION RESUME
Default handling of warnings in procedures and triggers
Using exception handlers in procedures and triggers
Nested compound statements and exception handlers