UPDATE CONSTRAINTS IN TRANSACTIONS WHICH MAY ABORT

摘要

A technique which may be used in a transaction which updates a data set when thedata set is subject to constraints and includes operations which may abort. The technique produces an update constraint which may be tested before the data set is altered to determine whether the constraints will be satisfied if the data set is altered. The update constraint of the technique indicates whether the constraints would be satisfied if the transaction could not abort. The update constraint is checked at the application level, while the constraints which cause an operation to abort are checked at the system level. An application of the update constraint to a relational data base embedded in a telephone switch is disclosed.