Integrity checking for nested transactions

The authors present a mechanism to specify and to validate consistency constraints in object oriented databases. Constraints are specified using preand post-conditions associated with an exception handling mechanism. During transaction run-time, they treat exceptions corresponding to errors (in this case, they use immediate exceptions which are processed immediately) or presumption of errors (in this case, they use deferred exceptions which are processed at the end of the transaction), in order to insure validation. To refine their mechanism, we enlarge it to nested transactions. Deferred exceptions can be processed at each node of the transaction tree. Using a predefined exception, they propagate an abort of a sub-transaction to its parent transaction. Thus, the parent transaction can choose among different policies for processing the sub-transaction abort