Postgres Triggers

In this section, we will look at

• What is a trigger and how it works
• When to use triggers?
• Examples of triggers

PostgreSQL Triggers are database callback functions, which are automatically performed/invoked when a specified database event occurs.

PostgreSQL trigger can be specified to fire on three different scenarios.

• Before the operation is attempted on a row (before constraints are checked and the INSERT, UPDATE or DELETE is attempted)

• After the operation has completed (after constraints are checked and the INSERT, UPDATE, or DELETE has completed)

• Instead of the operation (in the case of inserts, updates or deletes on a view)