Chapter 3. SQL Processing
Published Online: 27 JAN 2005
DOI: 10.1002/0471721379.ch3
Copyright © 2005 John Wiley & Sons, Inc.
Book Title
Relational Database Index Design and the Optimizers: DB2, Oracle, SQL Server, et al.
Additional Information
How to Cite
Lahdenmäki, T. and Leach, M. (2005) SQL Processing, in Relational Database Index Design and the Optimizers: DB2, Oracle, SQL Server, et al., John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/0471721379.ch3
Publication History
- Published Online: 27 JAN 2005
- Published Print: 24 JUN 2005
ISBN Information
Print ISBN: 9780471719991
Online ISBN: 9780471721376
- Summary
- Chapter
Keywords:
- SQL statements;
- SQL processing;
- SQL predicates;
- composite predicates;
- optimizers;
- access paths;
- execution plans;
- index slices;
- matching index scans;
- matching columns;
- index screening;
- screening columns;
- covering index;
- optimizer monitoring;
- optimizer assistance;
- optimizer statistics;
- FETCH calls;
- cursors;
- filter factor;
- selectivity;
- selectivity ratio;
- cardinality;
- index design;
- result tables;
- result table materialization;
- SQL Server;
- Oracle;
- DB2 for z/OS;
- DB2 for LUW
Summary
How indexes and tables are used to process SQL statements; SQL processing concepts; predicates. Optimizers and access paths; index slices, matching index scans and matching columns, index screening and screening columns; when the access path is chosen; monitoring the optimizer; helping the optimizer with statistics and the number of FETCH calls required. The very important concepts of filter factor, selectivity and cardinality, together with their impact on index design. The materialization of the result table and its implications.