Single-record constraints

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The scope of a single-record constraint is restricted to the columns of 1 table. In the constraint SQL you use a single table name in the FROM clause.

Example

Consider the business rule: "A reservation can only be canceled after the reservation is booked." This rule is implemented by a restrictive single-record constraint:

SELECT    '' violation
FROM      reservation
WHERE     cancel_date < book_date

The Rules Engine validates single-record constraints at record validation time, when the record is stored. Corrective single-record constraints are validated before restrictive single-record constraints.

See also

Restrictive single-record constraints

Corrective single-record constraints