Please note that the same Only one trigger can be defined for the same trigger event with the same trigger time old and new can be used to refer to the changed record in the trigger. Trigger event (insert/update/delete) Theīasic syntax of the trigger is as follows Shown:Īmong them: trigger_time is the trigger event of the trigger, which can be before (triggered before the check constraint) or after (triggered after the check constraint) trigger_event is the trigger event, including insert, update, and delete.
Monitoring event (insert/update/delete)Ĥ. Triggers are often used to strengthen data integrity constraints and business rules. The execution of is not called by the program, nor is it started manually, but triggered by events, for example, when a table is operated (insert, delete, update), it will be activated for execution. It is a special stored procedure related to table events.
It is a method for programmers and data analysts to ensure data integrity.
Trigger (trigger): monitor a certain situation and trigger a certain operation.
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