Proposed DSpace+2.0 Abstract Data Model

The diagram below outlines the proposed DSpace+2.0 Abstract Data Model worked out during the the DSpace Architectural Review Working Group meetings. This diagram includes the following additional features:

• Site: is provided to supply a top level context for both storing metadata and a top level for a DSpace instance. Site is more part of the concrete application model
• DSpaceObject: All Model objects extend a core DSpaceObject class. This class provides a base class within which to place common properties and associations shared across the entire data model.
• previousRevision: The model includes revisioning at the level of items. Here, previousRevision is an association to any previous revisions of the item, each revision is an item in its own right with a combination of the revision number and handle to reference it.
• Its was discussed in the meeting that "Bitstream" be replaced with a more appropriate label. But, even after a vote electing "File" as most appropriate, there were misgivings about its usage. I've left "File" out of the diagram and used "Content" to describe objects previously defined as "Bitstreams".
• "Metadata" in the model can refer to both simple fields (Dublin Core) and more complex metadata described in Files (METS, DDI, etc). The abstact model does not define this granularity of implementation.