Inventory

The Merritt inventory service provides a comprehensive catalog of information known about digital objects, versions, collections, and owners. Given the storage URL for an object manifest, the Inventory service pulls first the manifest, and then (based on the manifest) the object's system metadata (the files in the object's system directory, as well as various files in the producer directory with the mrt- prefix, if present). The information in these files is used to populate the Inventory database.

Merritt Inventory Component Diagram

Relationships

The relationships managed in the Inventory database are illustrated below. For each object, the database keeps track of:

• its parent collection
• its owner
• any secondary ("local") identifiers, such as DOIs
• Dublin Core metadata for the object
• user-supplied metadata (e.g. DataCite) for the object
• embargo information, if any
• all versions of the object
• all files in each version
• all replicas of each file
• audit information for each replica

Note that the Dublin Core and user metadata are stored as system files with the object along with its data files, but they are also cached in the database for quick access.

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