CREATE TRIGGER

Purpose

Creates a trigger for a table

Syntax

CREATE TRIGGER ON [<database>!]<table>

FOR DELETE | ONAFTERDELETE | INSERT | ONAFTERINSERT | UPDATE | ONAFTERUPDATE

AS <expression>

See Also

ADD TABLE, ALTER INDEX, ALTER TABLE, CONSTRAINTS, DATA TYPES, DELETE TRIGGER, DROP TABLE, GETENV(), INSERT, SELECT, SET AUTOCATALOG, SET XMLFORMAT,

Description

The CREATE TRIGGER command is used to create a trigger for the specified table. Triggers cause the logical <expression> to be evaluated when certain operations are attempted.

Trigger	Operation
DELETE	Attempt to delete an existing record. Corresponds to onbeforedelete trigger in listings.
ONAFTERDELETE	After deleting an existing record
INSERT	Attempt to add a new record. Corresponds to onbeforeinsert trigger in listings.
ONAFTERINSERT	After adding a new record
UPDATE	Attempt to modify an existing record. Corresponds to onbeforeupdate trigger in listings.
ONAFTERUPDATE	After modifying an existing record

If the <expression> evaluates to False (.F.) the operation does not complete. If the <expression> evaluates to True (.T.) the operations does complete.

Keywords	Description
database	The name of the database to which the table belongs.
table	The name of the table
FOR DELETE | ONAFTERDELETE | INSERT | ONAFTERINSERT | UPDATE | ONAFTERUPDATE	Specifies the type of trigger to be created.
expression	A logical expression to be evaluated

Example

CREATE TRIGGER ON customers FOR UPDATE AS not empty(custid)