Relationships between Document Types

Frequently, this is handled by basing one document type on another, but sometimes there is no way for that to work. For instance, a custom DITA Map specialization, whose parent document type is the built-in "DITA" document type, might reference a domain specialization stored in a separate document type. Since that domain is not part of the basic "DITA" document type, it cannot be included via inheritance.

In situations such as this, you can make the catalog entries from one doctype available to another by adding it to that document type's XML Configuration. Click the XML Configuration tab of the document type that needs to reference an external module, and add the other document type to the list. Modules in the source document type may now reference the Public IDs, System IDs, and URIs that are defined in the other document type's catalog file.