Nets in data bases
Up to the present, contributions of General Net Theory to the field of database research and development are restricted to a few selected topics which, however, are of central concern. Two particular areas shall be addressed here: access synchronization and conceptual schema.
Access synchronization deals with the question of how to organize the accesses of users at different sites to a distributed database such that deadlocks and database inconsistencies can be avoided or detected and remedied. The use of PrT-nets to model such an access protocol is demonstrated. It is shown how formal algebraic methods can be applied to prove essential properties of the specified access protocol.
The conceptual schema is intended to be a formally modelled information system that contains exactly all knowledge about those invariant properties of the real system in mind which are regarded as relevant in the given context and form the starting point for a database design process. This includes static and dynamic constraints. The principles of modelling conceptual schemas with nets and of an integrated treatment of static and dynamic aspects shall be exemplified.
KeywordsData Item Conceptual Schema Concurrency Control Read Request Database Theory
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