Difference between revisions of "ONUPDATE Table Constraint"
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==Purpose== | ==Purpose== | ||
Table constraint activated when an attempt is made to update a record in the table | Table constraint activated when an attempt is made to update a record in the table | ||
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==Syntax== | ==Syntax== | ||
ONUPDATE <procedure> | ONUPDATE <procedure> | ||
| + | ONBEFOREUPDATE <procedure> | ||
==See Also== | ==See Also== | ||
[[ALTER TABLE]], [[SQL Constraints|CONSTRAINTS]], [[CREATE TABLE]] | [[ALTER TABLE]], [[SQL Constraints|CONSTRAINTS]], [[CREATE TABLE]] | ||
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==Description== | ==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. | 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 ONUPDATE table constraint is activated when an attempt is made to update 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 update the record is executed and must return True (.T.) or the update operation is cancelled. | + | The ONUPDATE / ONBEFOREUPDATE table constraint is activated when an attempt is made to update 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 update the record is executed and must return True (.T.) or the update operation is cancelled. |
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==Example== | ==Example== | ||
<code lang="recital"> | <code lang="recital"> | ||
ALTER TABLE customer; | ALTER TABLE customer; | ||
| − | modify ONUPDATE " | + | modify ONUPDATE "customer_onupdate" |
| + | ALTER TABLE customer; | ||
| + | modify ONBEFOREUPDATE "customer_onbeforeupdate" | ||
</code> | </code> | ||
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[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL]] | [[Category:SQL]] | ||
Latest revision as of 07:32, 21 November 2012
Contents
Purpose
Table constraint activated when an attempt is made to update a record in the table
Syntax
ONUPDATE <procedure>
ONBEFOREUPDATE <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 ONUPDATE / ONBEFOREUPDATE table constraint is activated when an attempt is made to update 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 update the record is executed and must return True (.T.) or the update operation is cancelled.
Example
ALTER TABLE customer; modify ONUPDATE "customer_onupdate" ALTER TABLE customer; modify ONBEFOREUPDATE "customer_onbeforeupdate"
