Difference between revisions of "CHECK Table Constraint"
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==Purpose== | ==Purpose== | ||
Table constraint activated when an operation to insert, update or delete records in the table is called | Table constraint activated when an operation to insert, update or delete records in the table is called | ||
Revision as of 15:09, 29 October 2009
Purpose
Table constraint activated when an operation to insert, update or delete records in the table is called
Syntax
CHECK <condition>
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 CHECK table constraint is activated when an operation to insert, update or delete records in the table is called. The <condition> specified must evaluate to True (.T.) for the operation to succeed. If the <condition> evaluates to False (.F.) the operation is abandoned and the ERROR table constraint message is displayed. If the ERROR table constraint has not been defined, a default error message is displayed.
Example
set sql to vfp CREATE TABLE purchase_order (POid i PRIMARY KEY, SuppId i, POtotal n(10,2), ; CHECK callauth() ERROR [Not authorized])
Products
Recital Database Server, Recital Mirage Server, Recital Terminal Developer
