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XML Tree
XML documents have a hierarchical structure and can conceptually be interpreted as a tree structure, called an XML tree. XML documents must contain a root element (one that is the parent of all other elements). All elements in an XML document can contain sub elements, text and attributes. The tree represented by an XML document starts at the root element and branches to the lowest level of elements. Although there is no consensus on the terminology used on XML Trees, at least two standard terminologies have been released by the W3C: * The terminology used in the XPath Data Model * The terminology used in the XML Information Set. XPath defines a syntax named ''XPath expressions'' that identifies one or more internal components (elements, attributes, etc.) of an XML document. XPath is widely used to accesses XML-encoded data. The XML Information Set, or XML infoset, describes an abstract data model for XML documents in terms of information items. It is often used in the specifica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XPath
XPath (XML Path Language) is an expression language designed to support the query or transformation of XML documents. It was defined by the World Wide Web Consortium (W3C) and can be used to compute values (e.g., strings, numbers, or Boolean values) from the content of an XML document. Support for XPath exists in applications that support XML, such as web browsers, and many programming languages. Overview The XPath language is based on a tree representation of the XML document, and provides the ability to navigate around the tree, selecting nodes by a variety of criteria. In popular use (though not in the official specification), an XPath expression is often referred to simply as "an XPath". Originally motivated by a desire to provide a common syntax and behavior model between XPointer and XSLT, subsets of the XPath query language are used in other W3C specifications such as XML Schema, XForms and the Internationalization Tag Set (ITS). XPath has been adopted by a number of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XML Information Set
XML Information Set (XML Infoset) is a W3C specification describing an abstract data model of an XML document in terms of a set of ''information items''. The definitions in the XML Information Set specification are meant to be used in ''other'' specifications that need to refer to the information in a well-formed XML document. An XML document has an information set if it is well-formed and satisfies the namespace constraints. There is no requirement for an XML document to be valid in order to have an information set. An information set can contain up to eleven different types of information items: #The Document Information Item (always present) #Element Information Items #Attribute Information Items # Processing Instruction Information Items #Unexpanded Entity Reference Information Items #Character Information Items #Comment Information Items #The Document Type Declaration Information Item #Unparsed Entity Information Items #Notation Information Items #Namespace Information Item ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree (graph Theory)
In graph theory, a tree is an undirected graph in which any two vertices are connected by ''exactly one'' path, or equivalently a connected acyclic undirected graph. A forest is an undirected graph in which any two vertices are connected by ''at most one'' path, or equivalently an acyclic undirected graph, or equivalently a disjoint union of trees. A polytreeSee . (or directed tree or oriented treeSee .See . or singly connected networkSee .) is a directed acyclic graph (DAG) whose underlying undirected graph is a tree. A polyforest (or directed forest or oriented forest) is a directed acyclic graph whose underlying undirected graph is a forest. The various kinds of data structures referred to as trees in computer science have underlying graphs that are trees in graph theory, although such data structures are generally rooted trees. A rooted tree may be directed, called a directed rooted tree, either making all its edges point away from the root—in which case it is called an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
