Tamino XQuery User Guide - Software AG Documentation

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Advanced Usage This chapter covers some advanced XQuery usage. This functionality is partly tied to using Tamino query pragmas that affect the processing of the query. With Tamino query pragmas you can import modules and add declarations for namespaces and collations as well as functions and external variables. They have the syntactic form {?piname?}, which is why they were previously called XQuery processing instructions. This chapter discusses some of these concepts: Another important area of advanced XQuery usage is related to performance questions and optimizing your Tamino XQuery programs. You can find more information about this topic in the Performance Guide. Namespaces A namespace declaration defines a namespace prefix and associates it with a valid namespace URI. This namespace declaration is valid throughout the query expression. For example, you can define your own namespace: declare namespace dotcom="http://company.dot.com/namespaces/corporate" for $a in input()/bib/book return { $a } It is an error (INOXQE 6356) to redefine a namespace: declare namespace dotcom="http://company.dot.com/namespaces/corporate" declare namespace dotcom="http://company.dot.com/new-namespaces/corporate" for $a in input()/bib/book return { $a } But you can use two different namespaces at the same time: declare namespace dotcom="http://company.dot.com/namespaces/corporate" declare namespace tf="http://namespaces.softwareag.com/tamino/TaminoFunction" for $a in input()/bib/book where tf:containsText($a/title, "UNIX") return { $a } You can also declare default namespaces that can be applied to elements or attributes alike. 76 XQuery User Guide
Advanced Usage declare default element namespace "http://company.dot.com/namespaces/corporate" for $a in input()/bib/book return { $a } The default element namespace applies to all unqualified element names, in both expressions and constructors, unless a different default namespace is defined in an inner scope, as shown in the following example: declare default element namespace "X" declare namespace y="Y" let $x := {element x2{{element x4{}}}} return $x/x2/y:x3/y:x4 In this example, the default element namespace applies to all occurrences of x1 and x2; however, it does not apply to x3 and x4, because their default namespace is defined by the inner specification xmlns="Y". The default element namespace does not apply to attribute names. There is no default attribute namespace. There is a default function namespace. It applies to function names in function definitions and function calls. Tip: You need not declare a namespace in the prolog if you use one of the predeclared namespaces. You can find the list of predeclared namespaces in the description of NamespaceDecl in the XQuery Reference Guide User-Defined Functions In addition to the large set of XQuery functions as defined by the W3C and those that are specific to Tamino, you can write your own functions. User-defined functions consist of a function header representing its signature and the function body containing an XQuery expression. The header consists of an identifier, a list of parameters and corresponding type information, and the type of the return value. Type information is optional: if you omit it, item* will be assumed. Note that the set of allowed types is restricted to all simple types and some common XQuery types (the reference description of FunctionDecl contains a complete list). The function identifier must be a QName together with a non-empty namespace prefix. To avoid introducing a new namespace for locally used functions, that is functions used in the current module, XQuery provides an implicit namespace to which the prefix local is bound. This is an example for a function that uses this local namespace: XQuery User Guide 77
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Tamino XQuery User Guide Version 9.
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Table of Contents Preface .........
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Preface This document describes how
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1 Sample bib This doctype describes
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2 Sample reviews This doctype descr
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3 Query Examples ■ Using Construc
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Query Examples This section contain
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Query Examples Explanation Again, a
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Query Examples Explanation Building
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Query Examples Explanation A join i
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Query Examples Deleting Nodes The f
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Query Examples Explanation For the
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4 The Nuts and Bolts of XQuery ■
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Page 42 and 43: FLWOR Expressions The order by and
Page 44 and 45: Performing Update Operations In Tam
Page 46 and 47: Performing Update Operations Renami
Page 48 and 49: Performing Update Operations Schema
Page 50 and 51: Performing Update Operations Note:
Page 52 and 53: Performing Update Operations update
Page 55 and 56: 7 Calling XQuery through a Web Serv
Page 57 and 58: Calling XQuery through a Web Servic
Page 67 and 68: 8 CRUD Usage of a Tamino Doctype as
Page 69 and 70: CRUD Usage of a Tamino Doctype as a
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Page 88 and 89: Advanced Usage Defining a Custom Ou
Page 91 and 92: 10 Text Retrieval ■ Simple Text S
Page 93 and 94: Text Retrieval for $a in input()/pa
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Page 97 and 98: Text Retrieval Data on the Web 34.
Page 99 and 100: Text Retrieval In Tamino, you can u
Page 101 and 102: Text Retrieval ■ Location The att
Page 103 and 104: Text Retrieval perp whelp carnivore
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Page 107 and 108: Text Retrieval 1. Contents Translat
Page 109 and 110: Text Retrieval path separator is no
Page 111 and 112: III Related Information 105
Page 113 and 114: 11 Related Information ■ Internal
Page 115 and 116: Related Information ■ XQuery 1.0
Page 117 and 118: Index A atomization, 30 C character
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