before_delete_trigger

BEFORE DELETE Trigger

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Description

A BEFORE DELETE Trigger means that MySQL will fire this trigger before the DELETE operation is executed.

Syntax

The syntax to create a BEFORE DELETE Trigger in MySQL is:

Parameters or Arguments

OR REPLACE: It is an optional parameter. It is used to re-create the trigger if it already exists. It facilitates you to change the trigger definition without using a DROP TRIGGER statement.

trigger_name : name of the trigger to create.

BEFORE DELETE: indicates that the trigger will fire before the DELETE operation is executed.

table_name : name of the table that the trigger is created on.

Restrictions

  • You can not create a BEFORE trigger on a view.
  • You can update the NEW values.
  • You can not update the OLD values.

Example

Let’s look at an example of how to create an BEFORE DELETE trigger using the CREATE TRIGGER statement in MySQL.

If you had a table created as follows:

We could then use the CREATE TRIGGER statement to create an BEFORE DELETE trigger as follows:

 

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Rasmi Ranjan

A tech guy who loves to learn code. I'm open source enthusiast and a delicious coffee maker

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