Transforming queries from a relational schema to an object schema: A prototype based on F-logic
This paper describes a technique to support interoperable query processing when multiple heterogeneous knowledge servers are accessed. The problem is to support query transformation transparently, so a user can pose queries locally, without the need of global knowledge about different data models and schema. In this paper, we focus on transforming SQL source queries, posed against a relational schema, to XSQL queries to be evaluated against an object schema, so that information can be shared. We will describe an extraction algorithm which extracts semantics from a source SQL query, and the query transformation algorithm, described by example mapping rules, which access mapping knowledge among the schema/models and the query languages. This knowledge is represented in a parameterized canonical form, using a second-order logic, namely F-logic.
KeywordsQuery Language Extraction Algorithm Global Schema Relational Schema Mapping Rule
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- Ahmed, R., J. Albert, W. Du, W. Kent: An overview of Pegasus. Proceedings of the International Conference on Data Engineering, (1993)Google Scholar
- Albert, J., R. Ahmed, M. Ketabchi, W. Kent, M. Shan: Automatic importation of relational schemas in Pegasus. Proceedings of the International Conference on Data Engineering. (1993)Google Scholar
- Arens, Y. and C. Knoblock: Planning and reformulating queries for semantically-modeled multidatabase systems. Proceedings of the International Conference on Knowledge Management. (1992)Google Scholar
- Dorr, Bonnie J.: Machine Translation: A View from the Lexicon. MIT Press. Cambridge, MA. (1993)Google Scholar
- Kifer, M. and G. Lausen: F-logic: A higher-order language for reasoning about objects, inheritance and scheme. Proceedings of the ACM Sigmod Conference. (1989)Google Scholar
- Kifer, M., W. Kim, and Y. Sagiv: Querying object-oriented databases. Proc. of the ACM Sigmod Conference. (1992)Google Scholar
- Kim, W., Choi, I., Gala, S. and Scheevel, M.: On resolving heterogeneity in multidata-base systems. Distributed and Parallel Databases, Vol. 1. (1993) 251–279Google Scholar
- Lawley, M.: A Prolog interpreter for F-logic. Technical report. Griffith University. (1993)Google Scholar
- Lefebvre, A., P. Bernus and R. Topor: Query transformation for accessing heterogeneous databases. Joint International Conference and Symposium on Logic Programming, Workshop on Deductive Databases. (1992)Google Scholar
- Qian, X.: Semantic interoperation via intelligent mediation. Workshop on Research Issues in Data Engineering. (1993)Google Scholar
- Raschid, L., Chang, Y. and B. Dorr: Interoperable Query Processing with Multiple Heterogeneous Knowledge Servers. Proceedings of the Second International Conference on Information and Knowledge Management. (1993)Google Scholar
- Raschid, L., Chang, Y. and B. Dorr: Query Transformation Techniques for Interoperable Query Processing in Cooperative Information Systems. Proceedings of the Second International Conference on Cooperative Information Systems. (1994)Google Scholar