B.3 Addressing and Querying

XPath

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XML Path Language is used for locating XML objects. W3C

Status

XPath became a W3C Recommendation in November 1999. The specification is published at http://www.w3.org/TR/xpath/. XPath 2.0 Working Drafts include the XQuery 1.0 and XPath 2.0 Data Model at http://www.w3.org/TR/xpath-datamodel/, XQuery 1.0 and XPath 2.0 Functions and Operators at http://www.w3.org/TR/xpath-datamodel/, XQuery 1.0 and XPath 2.0 Formal Semantics at http://www.w3.org/TR/xquery-semantics/, and XML Path Language (XPath) 2.0 at http://www.w3.org/TR/xpath20.

Description

XPath is a language for addressing parts of an XML document, designed to be used by both XSLT and XPointer. XPath 2.0 was expanded considerably to add support for W3C XML Schema information and XQuery.

XPointer

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XML Pointer Language is a standard for specifying paths in URIs. W3C

Status

Most of XPointer became a W3C Recommendation in March 2003. The specification is published in four parts. The XPointer Framework can be found at http://www.w3.org/TR/xptr-framework/. The XPointer xmlns Scheme can be found at http://www.w3.org/TR/xptr-xmlns/, and the XPointer element( ) Scheme can be found at http://www.w3.org/TR/xptr-element/. The XPointer xpointer( ) Scheme remains a Working Draft, and can be found at http://www.w3.org/TR/xptr-xpointer/.

Description

XPointer is designed to be used as the basis for a fragment identifier for any URI reference that locates a resource of Internet media type text/xml or application/xml. Based on the XML Path Language (XPath), XPointer supports addressing into the internal structures of XML documents. It allows for examination of a hierarchical document structure and choice of its internal parts based on properties such as element types, attribute values, character content, and relative position.

XQuery

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XML Query Language provides database-like query facilities for accessing web documents. W3C

Status

XQuery is under development at the W3C. The most recent Working Drafts were published in May 2003. They include the XQuery 1.0 and XPath 2.0 Data Model at http://www.w3.org/TR/xpath-datamodel/, XQuery 1.0 and XPath 2.0 Functions and Operators at http://www.w3.org/TR/xpath-functions/, XQuery 1.0 and XPath 2.0 Formal Semantics at http://www.w3.org/TR/xquery-semantics/, XSLT 2.0 and XQuery 1.0 Serialization at http://www.w3.org/TR/xslt-xquery-serialization/, XQuery Use Cases at http://www.w3.org/TR/xquery- use-cases /, and XQuery 1.0: An XML Query Language at http://www.w3.org/TR/xquery/.

Description

XQuery is a query language that uses XML as a data model and is bound with XPath. XQuery expressions look more like traditional query and data processing environments than XSLT and XPath, and they can be used in a variety of software environments.