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1.8.5.4 Stored Procedures and Triggers
Stored procedures are implemented in MySQL version 5.0. See section 18 Stored Procedures and Functions.
Triggers are scheduled for implementation in MySQL version 5.1. A trigger is effectively a type of stored procedure, one that is invoked when a particular event occurs. For example, you could set up a stored procedure that is triggered each time a record is deleted from a transactional table and that stored procedure automatically deletes the corresponding customer from a customer table when all their transactions are deleted.