Extensible Data Model

نویسنده

Manuk G. Manukyan

چکیده

We investigated the problems of support of XML databases. An extensible data model appears as a result of this research. The offered data model is considered as an XML application. Our approach of support of XML databases is an attempt to create a data model which is based on the XML data model and combines the best features of the relational and object databases. To model the database concepts the so-called content dictionary mechanism is used. The content dictionary mechanism is a fundamental concept of our approach by means of which the extensibility of considered data model is achieved. To give the semantic constraints relative to the database concepts a formal type system is applied. The same type system is used to define metadata. To support declarative queries an element calculus is developed. It is possible to define derivative entities, virtual databases, triggers, and general constraints. Database and metadata are considered evolving in time.

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