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A resource name can be directly specified (a literal string), a string generated through a mask, or a combination of both. Regardless of the format chosen, the resulting resource name must be unique within the authority path to which it belongs.

Literal string

A literal string is a constant set of characters for a resource name. Requesting a literal string means to fully specify the resource name that will be assigned to the digital object. An example of a literal string would be a local accession number used as the resource name.

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For example, if a still image being deposited has the local accession number sb8897, the resource name portion of the persistent identifier could be specified as:

   urn-3:FHCL:sb8897

URN mask

A URN mask is a placeholder that will be replaced with actual values by NRS. Mask fields may be added anywhere in the string and repeated. They are enclosed in braces { } to distinguish them from other parts of the string. The brace characters are not otherwise valid in a persistent identifier.

The URN mask fields defined in NRS are:

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Note that using a mask does not guarantee that the resulting string will be unique. If a non-unique value is generated, an error will result and a persistent identifier will not be created in NRS. To guarantee the generation of a unique persistent identifier, include the integer value {n} in the mask.

For example: