Nested Queries and Quantifiers in an Ordered Context

We present algebraic equivalences that allow to unnest nested algebraic expressions for order-preserving algebraic operators. We illustrate how these equivalences can be applied successfully to unnest nested queries given in the XQuery language. Measurements illustrate the performance gains possible by unnesting.

• Type: Conference
• Year: 2004
• Where: ICDE
• Authors: Norman May, Sven Helmer, Guido Moerkotte
• Keywords: Algebraic Equivalences, Database, ICDE 2004, Nested Algebraic Expressions