== Relations Datastream ==

The relations datastream (RELS-EXT) is defined by FoxML. It uses Resource Description Framework ([[http://www.w3.org/RDF/|RDF]]) to describe the relations.

For FedoraObjects the RELS-EXT datastream is optional, but for a DOMS object, the RELS-EXT datastream is mandatory. This is required by the typechecking mechanism. 

DOMS RDF uses the controlled vocabulary from Fedora, together with a generic DOMS controlled vocabulary and collection-specific controlled vocabularies.

The mandatory relations for objects of a specified type are defined by the TYPE object.