DB2 ® Version 9 Linux, UNIX, and Windows XQuery Reference SC18-9796-00 DB2 ® Version 9 Linux, UNIX, and Windows XQuery Reference SC18-9796-00 Note Note: Before using this information and the product it supports, read the information in Notices. Edition Notice This document contains proprietary information of IBM. It is provided under a license agreement and is protected by copyright law. The information contained in this publication does not include any product warranties, and any statements provided in this manual should not be interpreted as such. You can order IBM publications online or through your local IBM representative. v To order publications online, go to the IBM Publications Center at www.ibm.com/shop/publications/order. v To find your local IBM representative, go to the IBM Directory of Worldwide Contacts at www.ibm.com/planetwide. To order DB2 publications from DB2 Marketing and Sales in the United States or Canada, call 1-800-IBM-4YOU (426-4968). When you send information to IBM, you grant IBM a nonexclusive right to use or distribute the information in any way it believes appropriate without incurring any obligation to you. © Copyright International Business Machines Corporation 2006. All rights reserved. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Tables . .ix Figures . .xi Chapter 1. DB2 XQuery concepts . .1 Introduction to XQuery . .1 Comparison of XQuery to SQL . .2 Retrieving DB2 data with XQuery functions . .2 XQuery and XPath data model . .4 Sequences and items . .4 Atomic values . .4 Node hierarchies . .5 Node properties . .7 Node kinds . .7 Document order of nodes . .10 Node identity . .10 Typed values and string values of nodes . .10 Serialization of the XDM . .11 XML namespaces and QNames . .12 Qualified names (QNames) . .12 Statically known namespaces . .13 Language conventions . .14 Case sensitivity . .14 Whitespace . .14 Comments . .15 Where to find more information about XQuery . .15 Chapter 2. Type system . .17 The type hierarchy . .17 Types by category . .18 Constructor functions for built-in data types . .22 Type casting . .23 anyAtomicType data type . .25 anySimpleType data type . .25 anyType data type . .26 anyURI data type . .26 base64Binary data type . .26 boolean data type . .26 byte data type . .26 date data type . .26 dateTime data type . .27 dayTimeDuration data type . .28 decimal data type . .29 double data type . .29 duration data type . .30 ENTITY data type . .31 float data type . .31 gDay data type . .31 gMonth data type . .32 gMonthDay data type . .32 gYear data type . .32 gYearMonth data type . .33 hexBinary data type . .33 © Copyright IBM Corp. 2006 iii ID data type . .33 IDREF data type . .33 int data type . .34 integer data type . .34 language data type . .34 long data type . .34 Name data type . .34 NCName data type . .34 negativeInteger data type . .34 NMTOKEN data type . .35 nonNegativeInteger data type . .35 nonPositiveInteger data type . .35 normalizedString data type . .35 NOTATION data type . .35 positiveInteger data type . .35 QName data type . .35 short data type . .36 string data type . .36 time data type . .36 token data type . .37 unsignedByte data type . .37 unsignedInt data type . .37 unsignedLong data type . .37 unsignedShort data type . .37 untyped data type . .37 untypedAtomic data type . .37 yearMonthDuration data type . .38 Chapter 3. Prolog . .39 Version declaration . .39 Boundary-space declaration . .40 Construction declaration . .40 Copy-namespaces declaration . .41 Default element/type namespace declaration . .42 Default function namespace declaration . .42 Empty order declaration . .43 Ordering mode declaration . .44 Namespace declaration . .44 Chapter 4. Expressions . .47 Concepts for expression processing . .47 Dynamic context and focus . .47 Precedence . .47 Order of results in XQuery expressions . .48 Atomization . .50 Subtype substitution . .50 Type promotion . .51 Effective Boolean value . .51 Primary expressions . .52 Literals . .52 Variable references . .54 Parenthesized expression . .55 Context item expressions . ..