Triggers are provided by OceanBase Database for Oracle tenants. A trigger is similar to a procedure or function. It is a PL block that contains a declarative part, an executable part, and an exception-handling part. A trigger is executed when a specific event occurs. You can specify whether a trigger fires before or after an event. You can also specify whether a trigger fires for a specific event or fires for a row of data affected by an event.
Definition
A trigger is an independent object that is automatically and implicitly activated when a triggering statement is executed. A trigger does not accept parameters. The triggering statement can be an INSERT, UPDATE, or DELETE statement.
Note
OceanBase Database V2.2.7x and earlier versions support only row-level triggers on tables.
Trigger execution time
A simple trigger is executed at one of the following four points:
A statement-level BEFORE trigger is executed before the triggering event executes.
A statement-level AFTER trigger is executed after the triggering event executes.
A row-level BEFORE trigger is executed before a specific row is affected.
A row-level AFTER trigger is activated after a specific row is affected.
A DML statement may trigger many simple triggers, which are executed in the following order: statement-level BEFORE trigger -> row-level BEFORE trigger -> row-level AFTER trigger -> statement-level AFTER trigger. The execution order of the same type of trigger is uncertain. Currently, you cannot specify an execution order for triggers.