tailieunhanh - Lecture Database system concepts - Chapter 14: Query optimization

This chapter describes how queries are optimized. It starts off with statistics used for query optimization, and outlines how to use these statistics to estimate selectivities and query result sizes used for cost estimation. Equivalence rules are covered next, followed by a description of a query optimization algorithm modeled after the classic System R optimization algorithm, and coverage of nested subquery optimization. | Chapter 14: Query Optimization Database System Concepts 5th Ed. ©Silberschatz, Korth and Sudarshan See ­ for conditions on re­use Chapter 14: Query Optimization s Introduction s Transformation of Relational Expressions s Catalog Information for Cost Estimation s Statistical Information for Cost Estimation s Cost­based optimization s Dynamic Programming for Choosing Evaluation Plans s Materialized views Database System Concepts ­ 5th Edition, Sep 1, 2006. 14. ©Silberschatz, Korth and Sudarshan Introduction s Alternative ways of evaluating a given query q Equivalent expressions q Different algorithms for each operation Database System Concepts ­ 5th Edition, Sep 1, 2006. 14. ©Silberschatz, Korth and Sudarshan Introduction (Cont.) s .

• Cơ sở dữ liệu
• Database system concepts
• Lecture Database system concepts
• Database systems
• Database languages
• Database design
• Query optimization
• Database system architectures
• Relational database design
• Recovery system
• Transaction state
• Concurrency control
• Data analysis
• Information retrieval
• Parallel databases
• Distributed databases
• Advanced application development
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• Advanced transaction processing
• Relational databases
• Relational model
• Basic query structure
• Dynamic SQL
• Tuple relational calculus
• Entity relationship model
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• XML applications
• Physical storage media
• Static hashing
• Query processing