Enable Triggers

Summary: in this tutorial, you will learn how to enable a trigger or all triggers associated with a table.

Introduction to ALTER TABLE…ENABLE TRIGGER statement

In PostgreSQL, a trigger is a database object that automatically invokes a specified function when an event occurs on a table or view. These events include INSERT, UPDATE, DELETE, or TRUNCATE.

If a trigger is disabled, it doesn’t activate when the triggering event occurs. To activate the trigger, you’ll need to enable it.

To enable a trigger or all triggers associated with a table, you use the ALTER TABLE ... ENABLE TRIGGER statement:

ALTER TABLE table_name
ENABLE TRIGGER trigger_name |  ALL;

In this syntax:

• First, specify the name of the table to which the trigger belongs you want to enable in the ALTER TABLE clause.
• Second, specify the name of the trigger you want to enable in the ENABLE TRIGGER clause, or use the ALL option if you want to enable all triggers associated with the table.

Enabling trigger example

The following statement enables the salary_before_update trigger on the employees table:

ALTER TABLE employees
ENABLE TRIGGER salary_before_update;

The following example enables all triggers that belong to the employees table:

ALTER TABLE employees
ENABLE TRIGGER ALL;

Summary

• Use the ALTER TABLE ENABLE TRIGGER statement to enable a trigger or all triggers that belong to a table.