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Errors and warnings in procedures
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Error handling with ON EXCEPTION RESUME
If the ON EXCEPTION RESUME clause is included in the CREATE
PROCEDURE statement, the procedure checks the following statement when
an error occurs. If the statement handles the error, then the procedure does not
return control to the calling environment when an error occurs. Instead, it
continues executing, resuming at the statement after the one causing the error.
Note When a statement has several parts or clauses, such as IF, ELSE IF, END
IF, or FOR and END FOR, the “following statement” refers to the next new
statement, not a statement part.
The following statements are considered error-handling statements:
•IF
• SELECT @variable =
•CASE
• LOOP
•LEAVE
• CONTINUE
•CALL
•EXECUTE
• SIGNAL
• RESIGNAL
• DECLARE
The following example illustrates how this works.
Drop the procedures
Remember to drop both the InnerProc and OuterProc procedures before
continuing with the tutorial. You can do this by entering the following
commands in the command window:
DROP PROCEDURE OUTERPROC;
DROP PROCEDURE INNERPROC
The following demonstration procedures show what happens when an
application calls the procedure
OuterProc; and OuterProc in turn calls the
procedure
InnerProc, which then encounters an error. These demonstration
procedures are based on those used earlier in this section: