13.6.7 Condition Handling
- 13.6.7.1 DECLARE ... CONDITION Statement
- 13.6.7.2 DECLARE ... HANDLER Statement
- 13.6.7.3 GET DIAGNOSTICS Statement
- 13.6.7.4 RESIGNAL Statement
- 13.6.7.5 SIGNAL Statement
- 13.6.7.6 Scope Rules for Handlers
- 13.6.7.7 The MySQL Diagnostics Area
- 13.6.7.8 Condition Handling and OUT or INOUT Parameters
- 13.6.7.9 Restrictions on Condition Handling
Conditions may arise during stored program execution that require special handling, such as exiting the current program block or continuing execution. Handlers can be defined for general conditions such as warnings or exceptions, or for specific conditions such as a particular error code. Specific conditions can be assigned names and referred to that way in handlers.
To name a condition, use the DECLARE ... CONDITION
statement. To declare a handler, use the DECLARE ... HANDLER
statement. See Section 13.6.7.1, “DECLARE ... CONDITION Statement”, and Section 13.6.7.2, “DECLARE ... HANDLER Statement”. For information about how the server chooses handlers when a condition occurs, see Section 13.6.7.6, “Scope Rules for Handlers”.
To raise a condition, use the SIGNAL
statement. To modify condition information within a condition handler, use RESIGNAL
. See Section 13.6.7.1, “DECLARE ... CONDITION Statement”, and Section 13.6.7.2, “DECLARE ... HANDLER Statement”.
To retrieve information from the diagnostics area, use the GET DIAGNOSTICS
statement (see Section 13.6.7.3, “GET DIAGNOSTICS Statement”). For information about the diagnostics area, see Section 13.6.7.7, “The MySQL Diagnostics Area”.