Query Optimization in OODB
In object-oriented databases, relationships are generally maintained explicitly. The partial result of a retrieved object can be used to efficiently retrieve related objects. Instead of optimizing joins as in relational database systems, pointer chasing is optimized in object-oriented database syste...
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| Main Authors: | , , |
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| Format: | text |
| Language: | English |
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Institutional Knowledge at Singapore Management University
1992
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| Subjects: | |
| Online Access: | https://ink.library.smu.edu.sg/sis_research/2876 https://ink.library.smu.edu.sg/context/sis_research/article/3876/viewcontent/OODB_1991_DASFAA.pdf |
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| Institution: | Singapore Management University |
| Language: | English |
| Summary: | In object-oriented databases, relationships are generally maintained explicitly. The partial result of a retrieved object can be used to efficiently retrieve related objects. Instead of optimizing joins as in relational database systems, pointer chasing is optimized in object-oriented database systems. Further, semantics inherent in the object-oriented database, like superclass-subclass relationships and composite-component relationships between object classes, must be realised. In this paper, we describe our initial result in query optimization in an object-oriented database system. Semantic query transformation is used to preprocess the query. semantically optimized query is then translated into a query evaluation plan which comprises method invocations that can be evaluated directly by the system. In the process of query evaluation plan generation, initial results tend to show that a one source query plan is almost optimal. A prototype based on this design has been completed and some results from a simulation study on this prototype are also reported in this paper. |
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