This document discusses revising the approach for modeling relationships between items in DSpace to make it more flexible and extensible. The initial approach involved new DSpace object types for different relationship types, but this would require a new code release each time a new type of complex object was supported. The revised approach uses generic relationship types of "hasPart" and "isPartOf" that can connect any kind of items. Relationships can be created and exposed via the user interface and APIs to provide a flexible way to model complex archival objects and collections in DSpace.

1. Durable Item Relations for DSpace

2. OVERVIEW
Context
DSpace 4 out of the box
Initial approach
Revised approach
Creating and managing relations
Conclusions

3. CONTEXT
What is the resemblance between

4. CONTEXT

5. CONTEXT

6. GOOD ANSWERS
Based in Flanders
Subject to annual environment reports

7. ANNUAL ENVIRONMENT REPORTS
A complex object with different parts and
attachments
Metadata recorded and represented in XML
Mix of confidential and public data
Prime usecase for digital preservation, open data
and archiving at the Flemish government

8. DSPACE 4 OUT OF THE BOX
One-to-many relationships
Community > Collection > Item > Bundle > Bitstream
Metadata and search: Item as the central object
Not optimized for large numbers of collections
Resource policies

9. INITIAL APPROACH
Typed items: “Document” Items vs “Dossier” Items
Typed relations ... as a new DSObject
Cardinality and type enforced

10. INITIAL APPROACH - NEW DSPACE OBJECTS

11. SERVICE IMPLEMENTATION

12. SERVICE IMPLEMENTATION

13. SERVICE IMPLEMENTATION

14. INITIAL APPROACH - NEW DSPACE OBJECTS

15. INITIAL APPROACH - EXTENSIBILITY
“How do we add archiving support for
another application with a different kind of
complex object?”
Answer: adding new RelationshipTypes,
Relationships and Typed objects in the
DSpace Java codebase.

16. “A new release of our DSpace codebase, every time we
want to support a new set of complex objects?”
“Yeah - that’s not going to fly”

18. REVISED APPROACH
Generic relationship-types: hasPart and isPartOf
No more typed items - allow these relations
between all kinds of items

19. CREATING RELATIONSHIPS
SWORD Package deposit for an entire archival
package. Results in different related items
Shared codebase with CLI Item ingestion tools
UI for creating and modifying relationships not
in scope yet

20. EXPOSING RELATIONSHIPS
Item pages list related items, and the nature of
the relation (hasPart and isPartOf)
Relations are indexed in Discovery as well for
exposure via SOLR
Soon: relationships exposed via REST API

21. CONCLUSION
Enforcing cardinality
DSpace 5 features
Metadata 4 all
Better performance for many collections
Contribution - Looking for feedback!

22. IMAGE CREDITS
Oriol Salvador https://www.flickr.com/photos/boarderland/
Steve Taylor https://www.flickr.com/photos/esartee/
Tiochorchi http://tiochorchi.deviantart.com/