Editing XPath 2.0 (section)

== Data model ==
{{Main|XQuery and XPath Data Model}}

Every value in XPath 2.0 is a ''sequence'' of ''items''. The items may be ''nodes'' or ''atomic values''. An individual node or atomic value is considered to be a sequence of length one. Sequences may not be nested.

Nodes are of seven kinds, corresponding to different constructs in the syntax of [[XML]]: elements, attributes, text nodes, comments, processing instructions, namespace nodes, and document nodes. (The document node replaces the ''root node'' of [[XPath 1.0]], because the XPath 2.0 model allows trees to be rooted at other kinds of node, notably elements.)

Nodes may be typed or untyped. A node acquires a type as a result of validation against an [[XML Schema (W3C)|XML Schema]]. If an element or attribute is successfully validated against a particular complex type or simple type defined in a schema, the name of that type is attached as an annotation to the node, and determines the outcome of operations applied to that node: for example, when sorting, nodes that are annotated as integers will be sorted as integers.

Atomic values may belong to any of the 19 primitive types defined in the [[XML Schema (W3C)|XML Schema]] specification (for example, string, boolean, double, float, decimal, dateTime, QName, and so on). They may also belong to a type derived from one of these primitive types: either a built-in derived type such as integer or Name, or a user-defined derived type defined in a user-written schema.