Trigger Uses

Triggers are useful in these ways:

Triggers can cascade changes through related tables in the database; however, these changes can be executed more efficiently using cascading referential integrity constraints.


Triggers can enforce restrictions that are more complex than those defined with CHECK constraints.
Unlike CHECK constraints, triggers can reference columns in other tables. For example, a trigger can use a SELECT from another table to compare to the inserted or updated data and to perform additional actions, such as modify the data or display a user-defined error message.

Triggers can also evaluate the state of a table before and after a data modification and take action(s) based on that difference.


Multiple triggers of the same type (INSERT, UPDATE, or DELETE) on a table allow multiple, different actions to take place in response to the same modification statement.