BEAAquaLogic® Data Services Platform XQuery and XQSE Developer’s Guide Note: Product documentation may be revised post-release and made available from the following BEA e-docs site: http://e-docs.bea.com/aldsp/docs30/index.html Version: 3.0 Document Date: June 2005 Revised: January 2008 Contents Introducing the AquaLogic Data Services Platform XQuery Engine XML and XQuery . 1-2 XQuery Use in AquaLogic Data Services Platform. 1-2 Supported XQuery Specifications . 1-3 Learning More About the XQuery Language . 1-3 BEA’s XQuery Implementation BEA XQuery Function Implementation . 2-2 Function Overview . 2-3 Access Control Functions. 2-7 Duration, Date, and Time Functions. 2-9 Execution Control Functions. 2-14 Numeric Functions . 2-20 Other Functions . 2-22 QName Functions . 2-24 Sequence Functions . 2-24 String Functions . 2-25 Extended XQuery Data Model (XXDM) Functions . 2-31 Unsupported XQuery Functions . 2-32 Implementation-Specific Functions and Operators . 2-33 BEA XQuery Language Implementation. 2-34 XQuery Developer’s Guide iii XQuery Language Support (and Unsupported Features) . .2-34 Extensions to the XQuery Language in the AquaLogic Data Services Platform XQuery Engine 2-34 Implementation-Defined Values for XQuery Language Processing . .2-38 XQuery Engine and SQL Introduction . .3-2 Base and Core RDBMS Support . .3-3 How the XQuery Engine Supports SQL Data Sources . .3-4 XQuery-SQL Data Type Mappings . .3-6 SQL Pushdown: Performance Optimization . .3-9 Common Query Patterns. .3-15 Grouping and Aggregation . .3-23 Direct SQL Data Services and Pushdown . .3-31 Distributed Query Pushdown . .3-32 Preventing SQL Pushdown . .3-33 Understanding XML Namespaces Introducing XML Namespaces . .4-1 Exploring XML Schema Namespaces . .4-2 Using XML Namespaces in AquaLogic Data Services Platform Queries and Schemas . .4-3 Best Practices Using XQuery Introducing Data Service Design . .5-2 Understanding Data Service Design Principles . .5-3 Applying Data Service Implementation Guidelines. .5-5 BEA XQuery Scripting Extension (XQSE) Introducing the XQuery Scripting Extension . .6-2 iv XQuery Developer’s Guide Prolog and Query Body . 6-2 Procedure Declaration . 6-2 XQSE Function Declaration. 6-3 Value Statement and Procedure Call . 6-4 Block. 6-4 Set Statement . 6-6 While Statement . 6-6 Return Statement . 6-7 Iterate Statement . 6-8 Try Statement . 6-9 If Statement. 6-10 Changed Element . 6-11 XQSE Grammar Summary . 6-12 XQuery-SQL Mapping Reference IBM DB2/NT 8 (and higher) . 7-2 Data Type Mapping . 7-2 Function and Operator Pushdown . 7-3 Cast Operation Pushdown . .7-4 Other SQL Generation Capabilities . 7-5 Microsoft SQL Server 2000 (and higher) . .7-6 Data Type Mapping . 7-6 Function and Operator Pushdown . 7-8 Cast Operation Pushdown . 7-10 Other SQL Generation Capabilities . 7-11 Oracle 8.1.x . 7-12 Data Type Mapping . 7-12 Function and Operator Pushdown . 7-13 XQuery Developer’s Guide v Cast Operation Pushdown. ..