There are two types of triggers:-
INSTEAD OF triggers
INSTEAD OF triggers fire in place of the triggering action. For example, if an INSTEAD OF UPDATE trigger exists on the Sales table and an UPDATE statement is executed against the Salestable, the UPDATE statement will not change a row in the sales table. Instead, the UPDATE statement causes the INSTEAD OF UPDATE trigger to be executed.
AFTER triggers
AFTER triggers execute following the SQL action, such as an insert, update, or delete. This is the traditional trigger which existed in SQL SERVER.
INSTEAD OF triggers are executed automatically before the Primary Key and the Foreign Key constraints are checked, whereas the traditional AFTER triggers is executed after these constraints are checked. Unlike AFTER triggers, INSTEAD OF triggers can be created on views.
