ALTER TRIGGER Statement

14.5 ALTER TRIGGER Statement

The ALTER TRIGGER statement enables, disables, compiles, or renames a database trigger.

Note:

This statement does not change the declaration or definition of an existing trigger. To redeclare or redefine a trigger, use the "CREATE TRIGGER Statement" with the OR REPLACE clause.

Topics

Prerequisites

If the trigger is in the SYS schema, you must be connected as SYSDBA. Otherwise, the trigger must be in your schema or you must have ALTER ANY TRIGGER system privilege.

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

See Also:

"CREATE TRIGGER Statement" for more information about triggers based on DATABASE triggers

Syntax

alter_trigger ::=

Description of the illustration alter_trigger.eps

trigger_compile_clause ::=

Description of the illustration trigger_compile_clause.eps

(compiler_parameters_clause ::=)

Semantics

alter_trigger

schema

Name of the schema containing the trigger. Default: your schema.

trigger_name

Name of the trigger to be altered.

[ ENABLE | DISABLE ]

Enables or disables the trigger.

RENAME TO new_name

Renames the trigger without changing its state.

When you rename a trigger, the database rebuilds the remembered source of the trigger in the *_SOURCE static data dictionary views. As a result, comments and formatting may change in the TEXT column of those views even though the trigger source did not change.

{ EDITIONABLE | NONEDITIONABLE }

Specifies whether the trigger becomes an editioned or noneditioned object if editioning is later enabled for the schema object type TRIGGER in schema. Default: EDITIONABLE. For information about altering editioned and noneditioned objects, see Oracle Database Development Guide.

Restriction on NONEDITIONABLE

You cannot specify NONEDITIONABLE for a crossedition trigger.

trigger_compile_clause

Recompiles the trigger, whether it is valid or invalid.

See compile_clause and compiler_parameters_clause semantics.

Examples

Example 14-5 Disabling Triggers

The sample schema hr has a trigger named update_job_history created on the employees table. The trigger fires whenever an UPDATE statement changes an employee's job_id. The trigger inserts into the job_history table a row that contains the employee's ID, begin and end date of the last job, and the job ID and department.

When this trigger is created, the database enables it automatically. You can subsequently disable the trigger with this statement:

ALTER TRIGGER update_job_history DISABLE;

When the trigger is disabled, the database does not fire the trigger when an UPDATE statement changes an employee's job.

Example 14-6 Enabling Triggers

After disabling the trigger, you can subsequently enable it with this statement:

ALTER TRIGGER update_job_history ENABLE;

After you reenable the trigger, the database fires the trigger whenever an UPDATE statement changes an employee's job. If an employee's job is updated while the trigger is disabled, then the database does not automatically fire the trigger for this employee until another transaction changes the job_id again.