XML Schema Complete Reference, The

22.3. Check Constraints versus Triggers

For each of the individual datatypes, this chapter presents examples using both check constraints in table creation and insert and update triggers. Which is best depends on the datatype being implemented and other system considerations. Here are some considerations:

• Check constraints are far less verbose than triggers in terms of code.

• Check constraints are not PL/SQL procedures and thus have limited functionality.

• Other parts of the database may rely on triggers already or may have no triggers and already use check constraints.

• Besides the validation work required against the XML schema document, other validations may be required for the system. Triggers are a more natural fit because multiple triggers can ...