MySQL Trigger

MySQL triggers are nothing but a SQL statement stored in the database. When any event associate with a table is fired i.e. insert, update or delete a trigger is executed.

TRUNCATE statement delete the all data in a table but does not execute the triggers associated with this.

The different between trigger and stored procedure is trigger is called automatically when a event is fired but stored procedure must be called explicitly.

You can to define maximum six triggers for each table.

– BEFORE INSERT
– AFTER INSERT
– BEFORE UPDATE
– AFTER UPDATE
– BEFORE DELETE
– AFTER DELETE

MySQL triggers stored with the file name tbl_name.TRG (maps the triggers to table) and tbl_name.TRN (trigger definition).