A relational algebra for data/metadata integration in a federated database system

Catharine Wyss, Dirk Van Gucht
2001 Proceedings of the tenth international conference on Information and knowledge management - CIKM'01  
The need for interoperability among databases has increased dramatically with the proliferation of readily available DBMS and application software. Even within a single organization, data from disparate relational databases must be integrated. A framework for interoperability in a federated system of relational databases should be inherently relational, so that it can use existing techniques for query evaluation and optimization where possible and retain the key features of SQL, such as a
more » ... complexity and ease of query formulation. Our contribution is a LOGSPACE relational algebra, the Meta-Algebra (MA), for data/metadata integration among relational databases containing semantically similar information in schematically disparate formats. The MA is a simple yet powerful extension of the classical relational algebra (RA). The MA has a natural declarative counterpart, the Meta-Query Language (MQL), which we briefly describe. We state a result showing MQL and the MA are computationally equivalent, which enables us to algebratize MQL queries in fundamentally the same way as ordinary SQL queries. This algebratization in turn enables us to use MA equivalences to facilitate the application of known query optimization techniques to MQL query evaluation.
doi:10.1145/502585.502597 dblp:conf/cikm/WyssG01 fatcat:nptlgif53zey3lmrxnaf3mjph4