Deactivation between incoming data, preconditions and postconditions |
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At runtime, the Rules Engine makes a comparison between all incoming column values and the preconditions and postconditions of corrective UPDATE constraints. This comparison is made for each store-record event in which these constraints are involved. •If the column value and the precondition are mutually exclusive, the constraint need not be evaluated. •If the postcondition coincides with the column value, the constraint need not be evaluated either, since it could only set the column to the value it already has. Of course, this applies only if no other columns are potentially changed by the constraint.
See also Deactivation between constraints |
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