Deferred Constraints

Deferred constraints are constraints for which the Deferred attribute has been set. Deferred constraints are not evaluated until commit time. Constraints may only be deferred if they meet the following requirements:

·	The constraint must be corrective.

·	The constraint must be non-transitional.

You should defer a corrective constraint if you know that the correction need not be executed for each manipulated record. This way you will improve application performance.

Suppose you have a complicated price calculation constraint involving many tables. By setting this constraint to Deferred, you can avoid unnecessary price re-calculation on every manipulation on any of the tables mentioned in the constraint.