A view definition and query translation system for a high-level data model



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The purpose of this thesis is to design and implement a view definition and query translation system for Views on the Entity Category Relationship (ECR) model using GORDAS, a high level database language. Currently there are two possible approaches for schema design: top-down and bottom-up. Here the bottom-up approach is adopted. This means the external schemas/views are built upon the existing conceptual schema. In our implementation, GORDAS is extended to support view definitions for the ECR model. The technique of query modification is used to translate GORDAS queries against an ECR external schema into equivalent GORDAS commands against an ECR conceptual schema. The approach is based on that proposed for relational query languages, with differences due to the ECR model's support for entity sets and functional interrelationships.



Database management, Computers--Access control