XPATH
- XPath
- is used to navigate through elements and attributes in an XML document
- is a major element in W3C's XSLT standard
- is a syntax for defining parts of an XML document
- uses path expressions to navigate in XML documents
- contains a library of standard functions
- is a W3C recommendation
- XQuery and XPointer are both built on XPath expressions
XPATH Expressions
- XQuery and XPointer are both built on XPath expressions
- XPath uses path expressions to select nodes or node-sets in an XML document
- XPath expressions look very much similar to traditional computer file system
XPath in XSLT
- XPath is a major element in the XSLT standard
- XPath is the result of an effort to provide a common syntax and semantics for functionality shared between XSL Transformations [XSLT] and XPointer [XPointer]
- The primary purpose of XPath is to address parts of an XML [XML] document
- Xpath also provides basic facilities for manipulation of strings, numbers and booleans
- XPath uses a compact, non-XML syntax to facilitate use of XPath within URIs and XML attribute values
- XPath operates on the abstract, logical structure of an XML document, rather than its surface syntax
- XPath gets its name from its use of a path notation as in URLs for navigating through the hierarchical structure of an XML document
XPath node
- XPath models an XML document as a tree of different type of nodes such as element nodes, attribute nodes and text nodes
- XPath defines a way to compute a string value for each type of node
- XPath fully supports XML Namespaces. The name of a node is modelled as a pair consisting of a local part and a possibly null namespace URI; this is called an expanded name
- The primary syntactic construct in XPath is the expression
- XML documents are treated as trees of nodes
- The topmost element of the tree is called the root element
XPath Expression
- An expression matches the production Expr
- An expression is evaluated to yield an object, which has one of the following four basic types:
- node-set (an unordered collection of nodes without duplicates)
- boolean (true or false)
- number (a floating-point number)
- string (a sequence of UCS characters)
