The XQuery and XPath Data Model (XDM) is the data model shared by the XPath 2.0, XSLT 2.0, XQuery, and XForms programming languages. It is defined in a W3C recommendation.[1] Originally, it was based on the XPath 1.0 data model which in turn is based on the XML Information Set.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/91/XQuery_and_XPath_Data_Model_type_hierarchy.png/220px-XQuery_and_XPath_Data_Model_type_hierarchy.png)
The XDM consists of flat sequences of zero or more items which can be typed or untyped, and are either atomic values or XML nodes (of seven kinds: document, element, attribute, text, namespace, processing instruction, and comment). Instances of the XDM can optionally be XML schema-validated.
References
edit- ^ Anders Berglund, et al., XQuery 1.0 and XPath 2.0 Data Model, W3C, 2010, revised, 2015,