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Referencing an XML Schema

A XML Schema can be referenced from an XML document by defining the schemaLocation and noNamespaceSchemaLocation attributes.

  • The 'schemaLocation' attribute is used to reference XML Schema(s) that are defined in a target-namespace.

    <root xmlns="http://www.example.org"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.example.org example.xsd">

  • The schemaLocation attribute can contain a list of namespaces and schema-locations, separated by white-space.

  • You can define multiple namespaces/schema-location pairs to validate elements and attributes in different namespaces.

    <root xmlns="http://www.example.org" 
    xmlns:ns2="http://www.example2.com"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.example.org example.xsd 
                        http://www.example2.com example2.xsd">

  • The 'noNamespaceSchemaLocation' attribute is used to reference XML Schema(s) that are not defined in a target-namespace.

    <root xmlns="http://www.example.org"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="example.xsd">

  • The noNamespaceSchemaLocation attribute only contains schema-locations and no namespace-uris.

  • The schemaLocation/noNamespaceSchemaLocation attributes are in is the 'http://www.w3.org/2001/XMLSchema-instance' namespace.

    Note

    Normally the prefix 'xsi' is used to indicate the 'XML Schema Instance' namespace.

  • The schemaLocation/noNamespaceSchemaLocation attributes are provided as a hint for the XML Processor (the XML Processor is not obliged to use it).