How to create trigger in Mysql | #mysql #php #phpmysql

#mysql #trigger #phpmysql #development

A MySQL trigger is a database object that is associated with a table and is activated when a particular event occurs on the table. An event may be an INSERT, UPDATE, or DELETE operation on the table.

Triggers are defined using the CREATE TRIGGER statement and are executed automatically by the database server. A trigger consists of three parts: the trigger event, the trigger condition, and the trigger action.

The trigger event specifies the event that activates the trigger, such as an INSERT or UPDATE operation on the table.

The trigger condition specifies an additional condition that must be met for the trigger to be activated. For example, you can specify that the trigger should only be activated when a certain value is inserted into a particular column.

The trigger action is the code that is executed when the trigger is activated. This can be a single statement or a block of statements enclosed in BEGIN and END statements.

Triggers can be used to enforce business rules, maintain referential integrity, audit changes to data, and perform other tasks automatically when data is modified. However, it is important to use triggers judiciously and to ensure that they do not adversely affect the performance of the database.