Tesis leida en la Universidad de Aberdeen. 178 p.The salient points of this thesis are as follows:
• Object-Oriented Databases can help in solving the impedance mismatch problem
by introducing methods. However, methods have sometimes been overused in the
sense th at the code encapsulated refers not only to how the operation is implemented
but also to other kinds of knowledge that are implicit in the code. The
disadvantages of this approach for modelling integrity constraints, user-defined relationships
and active behaviour are pointed out.
• The ADAM Object-Oriented Database has been extended to allow the designer
to specify integrity constraints declaratively. A constraint equation approach is
implemented th at supports the inheritance of constraints.
• A need for semantic-rich user-defined relationships has been identified. In this thesis,
relationships are represented as objects. An approach to enhance the semantics
of relationships in both its structural and behavioural aspects is presented. The
most novel idea of the approach presented is the support of the inferred properties
and the operational semantics of relationships.
• Active Databases have recently become an im portant area of research. This thesis
shows how to extend an Object-Oriented Database with active capabilities. The
principal contribution lies in representing as ‘first-class’ objects not only the active
rules but also the rule manager itself. Hence, besides handling active rules as
any other object in the system, future requirements can be supported just by
specialising the current rule manager.
• Active rules have been proposed for several purposes. Several examples, are given
of the direct use of rules. However, higher level tools can be provided of which rule
