As an alternative to using triggers, you can use the referential integrity constraint of the create table statement to enforce referential integrity across tables in the database. However, referential integrity constraints cannot:
Cascade changes through related tables in the database
Enforce complex restrictions by referencing other columns or database objects
Perform “what if” analyses
Also, referential integrity constraints do not roll back the current transaction as a result of enforcing data integrity. With triggers, you can either roll back or continue the transaction, depending on how you handle referential integrity. Chapter 23, “Transactions: Maintaining Data Consistency and Recovery.”
If your application requires one of the above tasks, use a trigger. Otherwise, use a referential integrity constraint to enforce data integrity. Adaptive Server checks referential integrity constraints before it checks triggers so that a data modification statement that violates the constraint does not also fire the trigger. For more information about referential integrity constraints, see Chapter 8, “Creating Databases and Tables.”
