From Nested-Loop to Join Queries in OODB

H.J. Steenhagen, H.J. Steenhagen, Peter M.G. Apers, Henk Blanken, R.A. de By

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Most declarative SQL-like query languages for object-oriented database systems are orthogonal languages allowing for arbitrary nesting of expressions in the select-, from-, and where-clause. Expressions in the from-clause may be base tables as well as set-valued attributes. In this paper, we propose a general strategy for the optimization of nested OOSQL queries. As in the relational model, the translation/optimization goal is to move from tuple- to set-oriented query processing. Therefore, OOSQL is translated into the algebraic language ADL, and by means of algebraic rewriting nested queries are transformed into join queries as far as possible. Three different optimization options are described, and a strategy to assign priorities to options is proposed.
Original languageUndefined
Title of host publicationProceedings of 20th International Conference on Very Large Data Bases (VLDB 1994)
Place of PublicationSan Francisco, CA, USA
PublisherMorgan Kaufmann Publishers Inc.
Number of pages12
ISBN (Print)1-55860-153-8
Publication statusPublished - Sep 1994
Event20th International Conference on Very Large Data Bases, VLDB 1994 - Santiago de Chile, Chile
Duration: 12 Sep 199415 Sep 1994
Conference number: 20

Publication series

PublisherMorgan Kaufmann Publishers Inc.


Conference20th International Conference on Very Large Data Bases, VLDB 1994
Abbreviated titleVLDB
CitySantiago de Chile


  • EWI-7334
  • IR-66456
  • METIS-119772

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