Change Management in Objectbases

In OODBMSs type-specific methods are used for manipulating objects, in order to maintain the consistency of the database. This is, however, of little help for the method implementor as far as the model-inherent constraints are concerned. We propose a set of generic update operations, including operations for object evolution that maintain integrity constraints that can be expressed in database schemas. On the one hand integrity constraints such as types, class memberships, subtype-, subclass-relationships, class predicates, and inverse functions are kept consistent after update operations, on the other hand the capabilities to express semantics in a schema are chosen such that such a set of update operations exists. The update operations can be used for implementing type-specific update methods or directly by applications. We present an approach to consistently define update semantics for an object model including classes, views, and variables that is based on necessary and sufficient predicates akin to defined concepts in KL-ONE style languages.