Difference between revisions of "ONDELETE Table Constraint"

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=ONDELETE=
 
 
 
==Class==
 
Table Constraints
 
 
 
 
==Purpose==
 
==Purpose==
 
Table constraint activated when an attempt is made to delete a record in the table
 
Table constraint activated when an attempt is made to delete a record in the table
Line 26: Line 19:
 
==Example==
 
==Example==
 
<code lang="recital">
 
<code lang="recital">
ALTER TABLE customer modify ONDELETE "p_delete";
+
ALTER TABLE customer;
 +
  modify ONDELETE "p_delete"
 
</code>
 
</code>
  
  
 
==Products==
 
==Products==
Recital Database Server, Recital Mirage Server, Recital Terminal Developer
+
Recital, Recital Server
 
[[Category:Documentation]]
 
[[Category:Documentation]]
 
[[Category:SQL]]
 
[[Category:SQL]]

Latest revision as of 10:56, 22 December 2009

Purpose

Table constraint activated when an attempt is made to delete a record in the table


Syntax

ONDELETE <procedure>


See Also

ALTER TABLE, CONSTRAINTS, CREATE TABLE


Description

A constraint is used to define rules that help to provide data integrity. TABLE constraints apply to table-based operations. You must have ALTER privilege on the table. The table will be locked for EXCLUSIVE use during the operation.

The ONDELETE table constraint is activated when an attempt is made to delete a record in the table. The <procedure> specified must be a character expression evaluating to a procedure name. If no file extension is included, '.prg' is assumed. The specified procedure is run before the operation to delete the record is executed and must return True (.T.) or the delete operation is cancelled.


Example

ALTER TABLE customer;
  modify ONDELETE "p_delete"


Products

Recital, Recital Server