Propagation constraint: Difference between revisions

Revision as of 02:11, 11 October 2005

Revision as of 13:27, 10 January 2006

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According to [[Beynon-Davies]] (2004, p.108) "''[a] propagation constaintconstraint details what should happen to a related table when we update a row or rows of a target table''". He further states that for all [[relationship]]s, one should define how to handle deletions of target and related [[tuple]]s. There are three possibilities:

* Restricted Delete - cannot delete the target row until all rows that point to it (via [[foreign key]]s) have been deleted.

* Cascades Delete - can delete the target row and all rows that point to it (via foreign keys) are also deleted.