Creating and using triggers
A trigger is a special type of stored procedure that fires (executes) in response to an event. We typically use triggers to maintain data integrity rules that are too complicated to implement through constraints and referential integrity. We also use triggers to:
- Implement referential actions, such as cascading deletes
- Maintain an audit trail of changes
- Perform administrative tasks such as auditing and regulating database operations
- Compare data before and after modification
- Implement custom error messages
Triggers cannot support parameters and should not return values or result sets.
Microsoft SQL Server 2014 has two basic trigger types: DML triggers and DDL triggers.
You can write DDL and DML triggers as Transact-SQL ...