CREATE TRIGGER

Purpose

Triggers are defined using PL/SQL. Therefore, this section provides some general information but refers to Oracle Database PL/SQL Language Reference for details of syntax and semantics.

Use the CREATE TRIGGER statement to create a database trigger, which is:

• A stored PL/SQL block associated with a table, a schema, or the database or

• An anonymous PL/SQL block or a call to a procedure implemented in PL/SQL or Java

Oracle Database automatically executes a trigger when specified conditions occur.

Prerequisites

To create a trigger in your own schema on a table in your own schema or on your own schema (SCHEMA), you must have the CREATE TRIGGER system privilege.

To create a trigger in any schema on a table in any schema, or on another user's schema (schema.SCHEMA), you must have the CREATE ANY TRIGGER system privilege.

In addition to the preceding privileges, to create a trigger on DATABASE, you must have the ADMINISTER DATABASE TRIGGER system privilege.

If the trigger issues SQL statements or calls procedures or functions, then the owner of the trigger must have the privileges necessary to perform these operations. These privileges must be granted directly to the owner rather than acquired through roles.

Syntax

Triggers are defined using PL/SQL. Therefore, the syntax diagram in this book shows only the SQL keywords. Please refer to Oracle Database PL/SQL Language Reference for the PL/SQL syntax, semantics, and examples.

create_trigger::=

Description of the illustration create_trigger.gif

(plsql_source: See Oracle Database PL/SQL Language Reference.)

Semantics

OR REPLACE

Specify OR REPLACE to re-create the trigger if it already exists. Use this clause to change the definition of an existing trigger without first dropping it.

plsql_source

See Oracle Database PL/SQL Language Reference for the syntax and semantics of the plsql_source.