3.3.31 CREATE TRIGGER

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3 The SQL Language : 3.3 SQL Commands : 3.3.31 CREATE TRIGGER

CREATE TRIGGER -- define a new trigger
[ WHEN condition ]
{ WHEN exception [ OR exception ] [...] THEN
statement; [, ...] } [, ...]
CREATE TRIGGER defines a new trigger. CREATE OR REPLACE TRIGGER will either create a new trigger, or replace an existing definition.
If you are using the CREATE TRIGGER keywords to create a new trigger, the name of the new trigger must not match any existing trigger defined on the same table. New triggers will be created in the same schema as the table on which the triggering event is defined.
See Section 5 for more information about triggers.
condition is a Boolean expression that determines if the trigger will actually be executed; if condition evaluates to TRUE, the trigger will fire.
If the trigger definition includes the FOR EACH ROW keywords, the WHEN clause can refer to columns of the old and/or new row values by writing OLD.column_name or NEW.column_name respectively. INSERT triggers cannot refer to OLD and DELETE triggers cannot refer to NEW.
If the trigger includes the INSTEAD OF keywords, it may not include a WHEN clause. A WHEN clause cannot contain subqueries.
Determines whether the trigger should be fired once for every row affected by the triggering event, or just once per SQL statement. If specified, the trigger is fired once for every affected row (row-level trigger), otherwise the trigger is a statement-level trigger.
A variable, type, or REF CURSOR declaration.
An SPL program statement. Note that a DECLARE - BEGIN - END block is considered an SPL statement unto itself. Thus, the trigger body may contain nested blocks.
An exception condition name such as NO_DATA_FOUND, OTHERS, etc.

3 The SQL Language : 3.3 SQL Commands : 3.3.31 CREATE TRIGGER

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