Re: Procdures, triggers, alerters and rules

Darren
Procedures, are statements functions (what ever you want to call them)> that are stored at the db level (like repeated queries) . They are used because they reduce overhead (as thay only pass through the optimiser at compile time afterwards when called they use the qep they have calculated at compilation.

Triggers are set to occur AFTER an event happens ,normally to enforce business rules etc.
Examples would be when a worker is DELETEd from the EMPLOYEE table DELETE references to the worker from the ROSTER table.

Rules Are used to enforce integrity of the db. They are invoked BEFORE an event is written to permanent storage ie COMMITed. Examples would be don't allow the creation of an employee row in the ROSTER table if the employee doesn't exist on the employee table.

Alerters ( i haven't used)

Darren Received on Wed Jul 08 1998 - 00:00:00 CDT