AnsTut12db05 - Page 1 24/12/2009 CP5520 Answer to Tutorial...

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Page 1 24/12/2009 CP5520 Answer to Tutorial Week 12 : 24.1 What are the differences between row-level and statement-level active rules? Answer: In row-level triggering, the rule is triggered separately for each tuple. In statement-level triggering, the rule is triggered once for each triggering statement. 24.2 What are the differences among immediate, deferred, and detached consideration of active rule considerations? Answer: The rule consideration (also known as rule condition evaluation) checks whether the conditions evaluates to true or false (if it is true, then the trigger must be executed). In immediate consideration, the condition is valuated as part of the same transaction as the triggering event, and is evaluated immediately (before or after executing the triggering event). In deferred consideration the condition is evaluated at the end of the transaction that contains the triggering event. In detached consideration the condition is evaluated as a separate transaction. 24.3
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This note was uploaded on 12/23/2009 for the course DBST 663 taught by Professor Tba during the Spring '09 term at MD University College.

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AnsTut12db05 - Page 1 24/12/2009 CP5520 Answer to Tutorial...

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