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A Fedora repository includes a number of predefined namespace bindings (essentially, a mapping that connects a particular prefix to a URI, allowing for a more convenient and human-readable rendering of RDF).  Predefined namespaces include DC, FOAF, Fedora, and LDP, among others.  As additional namespaces are used in the course of depositing materials into the repository, each new namespace will automatically be bound to its own prefix the first time it is used.  Once a URI is bound to a particular namespace prefix, it cannot be changed. A full list of the bound namespaces for a given Fedora repository at any given moment can be seen in the HTTP REST interface, as a list of pre-populated "PREFIX ..." bindings in the SPARQL update query text-box.

System-Generated Prefixes

As noted above, as new namespaces are used for the first time, those namespaces will be bound permanently to particular prefixes.  Currently, if the first use of a particular namespace should occur in RDF that is POSTed or PUT to the repository without including a specific prefix binding supplied in the submitted graph, Fedora will bind the new namespace to a system-generated namespace in the form "nsXXX" where "XXX" is a padded integer that increases by one (001, 002, 003, etc.) as new namespaces are encountered.  While this behavior is not incorrect, it is inconvenient, and not necessarily user-friendly for human interaction with the repository.


In order to establish user-defined mappings between namespace prefixes and their namespaces, it is necessary that the first time a given namespace is used in Fedora, it have the desired namespace prefix defined in the document of that request.

Custom Namespace registry