Use the RAISE EXCEPTION statement to simulate an error or to generate an
error with a custom message. An ON EXCEPTION statement can trap the generated
error.
If you omit ISAM_error, the database server sets the ISAM error code to zero (0) when the exception is raised. If you want to specify error_text but not specify a value for ISAM_error, specify zero (0) as the value of ISAM_error.
The RAISE EXCEPTION statement can raise either system-generated exceptions
or user-generated exceptions. For example, the following statement raises
the error number -208 and inserts the text a missing file into the variable of the system-generated error message:
RAISE EXCEPTION -208, 0, 'a missing file';
Here the minus ( - ) symbol is required after the EXCEPTION keyword for
error -208; most error codes are negative integers.
The special error number -746 allows you to produce a customized
message. For example, the following statement raises the error number -746 and returns the quoted text:
RAISE EXCEPTION -746, 0, 'You broke the rules';
In the following example, a negative value for alpha raises exception -746 and provides a specific message
that describes the problem. The code should contain an ON EXCEPTION statement
that traps for an exception of -746.
FOREACH SELECT c1 INTO alpha FROM sometable
IF alpha < 0 THEN
RAISE EXCEPTION -746, 0, 'a < 0 found' -- emergency exit
END IF
END FOREACH
When the SPL routine executes and the IF condition is met, the database
server returns the following error:
-746: a < 0 found.
For more information about the scope and compatibility of exceptions, see ON EXCEPTION.
>>-RAISE EXCEPTION--SQL_error_var-------------------------------> >--+----------------------------------+--;--------------------->< '-,--ISAM_error--+---------------+-' '-,--error_text-'