There are two ways of taking appropriate action if an SQL statement was unsuccessful:
Query SQLSTATE and branch according to the status code
Use the WHENEVER statement
You can use WHENEVER to specify that, after execution of an SQL statement with an SQLSTATE ≠ '00xxx' and ≠ '01xxx', the program is to continue executing or is to branch to a certain part of the program where error handling is performed. You can specify branching within the program for two error classes:
NOT FOUND: no data available, e.g. when the end of a table is reached
SQLERROR: other errors that result in abortion of SQL statements
You can specify the WHENEVER statement more than once in a program. The specifications made in a WHENEVER statement are valid for all subsequent SQL statements in the program text up to the next WHENEVER statement for the same error class.