The repository shall be able to provide a complete list of all such identifiers and do spot checks for duplications.

A list of object identifiers can be generated anytime through the GUI or API. Users can do this for their institution, and administrators can for the entire repository. APTrust retains a record of deleted objects (tombstones) so that if they are re-deposited, that object’s history is maintained.

APTrust’s preservation repository enforces unique identifiers for all objects by implementing database record ids in the underlying database. If a depositor uploads an object with the same name, it will be merged into the existing object via the Update process. If a depositor deletes a bag, the object and file records remain in the database, but are marked with state = ‘D’, which means deleted. If the depositor re-uploads the same bag with identically-named files, we flip the D back to A, for Active. The IDs for the objects and files never change, regardless of the item’s state.

APTrust does not support de-duplication.