RelationTypes

A Relation defines how two objects are related to each other. For example, a document may have a relation of type "image_relation" to all the images it references. This way, when the user downloads (or checks out) the document from the server for editing, all the referenced images can be also downloaded by the client.

A RelationType defines what kind of relation the two objects have and if none, one or both are protected. If an object which is part of a relation is "protected", it may not be deleted when the other object is deleted. For example, if a HTML document has a relation to a PDF version of this document, the original version should not be deleted if the converted form is removed from the repository. But if the original HTML version is deleted, there is (usually) no reason for the converted PDF object to remain.