Abbreviated query interpretation in extended entity-relationship oriented databases
In order to express database queries, users are often required to understand large, complex database structures. It is important to relax this requirement by allowing users to express concise (abbreviated) queries, so that they can manage with partial, or even no knowledge of the database structure. Abbreviated queries involve only the specification of the objects that are relevant to the users. The main problem with abbreviated queries is to derive the corresponding full queries. In this paper we present a methodology to support the expression of abbreviated queries in Extended Entity- Relationship (EER) oriented relational databases, that is, relational databases whose schemas are translations of EER schemas. In EER-oriented databases, abbreviated queries can be represented by disconnected subgraphs of the corresponding EER diagrams. We propose a criterion for determining the connected subgraphs corresponding to such abbreviated queries. Our criterion is based on the robustness of the relational view corresponding to a connected subgraph of an EER diagram. View robustness expresses the capability of performing side-effect free updates via the view. We also investigate techniques that take advantage of specific properties of EER diagrams in order to reduce the complexity of finding the subgraphs that correspond to a given abbreviated query. 22 refs., 7 figs.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5326075
- Report Number(s):
- LBL-25337; CONF-8910295-1; ON: DE90003114
- Resource Relation:
- Conference: 8. international conference on entity-relationship approach, Toronto (Canada), 18-20 Oct 1989
- Country of Publication:
- United States
- Language:
- English
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