Each Schema document must be uniquely identified using a Uniform Resource Name (URN). Each Schema document has a version-independent as well as a version-specific URN.
An XML resolver should be used to uniquely identify an XML Schema in order to map to a local resource. The DITA specification includes both URN- and URL-based versions of the XML schemas. The URL versions are included as a convenience for use with tools that do not support catalog based resolution and are not normative.
The catalog identifiers use the following patterns.
|OASIS DITA Technical Committee||urn:oasis:names:tc:dita:xsd:filename.xsd:version|
|Subcommittee of the OASIS DITA Technical Committee||urn:oasis:names:tc:dita:spec:subcomittee-specialization:xsd:filename.xsd:version|
- subcomittee-specialization indicates the subcommittee and specialization, for example, "machinery" or "learning".
- filename is the base name of the document-type shell or module component.
- version either is a DITA version number (for example, 1.0, 1.1, 1.2, or 1.3) or is omitted entirely.
Note that "oasis" is the owner identifier; this indicates that the artifacts are owned by OASIS. The keyword "dita" is a convention that indicates that the artifact is DITA-related. The pattern "urn:oasis:names:tc:dita" is a convention that indicates that the artifact is DITA-related and defined by the OASIS DITA Technical Committee.