After a rule object is created, the rule is stored with the table in the database and is applied continuously. Whenever the execution of a statement satisfies an existing rule condition, that rule is fired, meaning that the database procedure associated with the rule is executed. There is no need for application code to explicitly enforce the rule.

It is also possible for a statement in a rule-invoked database procedure to fire another rule. Rules can be nested in this manner up to a maximum level specified by the DBMS configuration parameter, rule_depth.

Any user who has the privilege to access the table through the operation specified by the rule has implicit permission to fire the rule and execute its associated database procedure. For information on privileges and how they are defined, see the Security Guide.