Built-in schemas

Saxon includes built-in schemas for a number of namespaces.

These fall into two categories:

• Hard-coded namespaces

  Schemas for certain namespaces are hard-coded into the Saxon schema processor and cannot be replaced or extended in any way. The namespaces in this category are:

  • The xml namespace http://www.w3.org/XML/1998/namespace which defines attributes such as xml:space and xml:id.

  • The fn namespace http://www.w3.org/2005/xpath-functions which defines the structure of the document returned by fn:analyze-string() and also the XML representation of the JSON data model.

  • The xsi namespace http://www.w3.org/2001/XMLSchema-instance which defines attributes such as xsi:type and xsi:schemaLocation.

• Cached namespaces

  Schemas for certain namespaces are held locally in the standard xmlresolver data cache which Saxon uses by default. If you reference one of these schemas in an xs:import declaration, Saxon will ignore any location hint in the schemaLocation attribute, and use its local copy in preference. If you want to use a non-standard version of one of these schemas from a location of your own choosing, you can use Saxon's resolver mechanisms to achieve this: for example you can supply your own ResourceResolver callback, or you can register a catalog file that redirects the namespace URI to a different location.

  The schemas in this category are:

  • The xlink namespace http://www.w3.org/1999/xlink

  • The xhtml namespace http://www.w3.org/1999/xhtml

  • The xsd namespace http://www.w3.org/2001/XMLSchema

  • The xslt namespace http://www.w3.org/1999/XSL/Transform