Plugins/ItemRelations 2.0

The Item Relations plugin lets you define relations between items. For example, you can make one item a part of another item, where "part of" is the relation. You can also make one item a "reproduction of" or a "translation of" another item.

We've bundled the plugin with common relations derived from several formal vocabularies, including Dublin Core, FRBR, FOAF, and BIBO. You may use these or create a custom vocabulary with the relations needed in your site. You could, for example, define custom relations like "is parent of," "is better than," and "fits within."

Instructions

After you install the plugin you'll be given the opportunity to configure it.

  1. Decide if you want to display an item's relations on its public show page
  2. Select the format of an item's relations that you'd prefer to appear on the item page: prefix:localPart or the label given to that relationship.

Customize Relationship Vocabulary

On the "Item Relations" tab in the left side of the admin navigation you will find the vocabularies available and their properties (a more general term for relations).

If you wish to create your own vocabulary, edit the "Custom" vocabulary by clicking on "Edit Custom Vocabulary" in its property show page. Here you can add, edit, and delete properties in your custom vocabulary.

Relating Items

When adding or editing an item, click on the "Item Relations" tab, at the top of the admin/item page to relate the item to another item, or to delete existing relations.

To relate need the item ID of the other item to define a relation.

You may batch relate items using the Batch Edit function from the Browse Items pages in the admin.

Item Relations and RDF

The plugin follows the RDF model for defining relations between items. There's a subject item, a predicate (a relation/property in this case), and an object item. If we decompose the sentence: "Item 1 is a part of Item 2," "Item 1" is the subject, "is a part of" is the predicate, and "Item 2" is the object. These triples are the foundation of RDF. Your end users won't have to know this, but it's helpful to know it as an administrator.

Following RDF, every formal vocabulary has a namespace prefix and namespace URI, which provide unambiguous context for its relations/properties. Every property has a local part and/or label, which are machine-readable and human-readable names of the property, respectively. As an administrator you'll only need to create labels, everything else is there for XML and RDFS compliance, to be used for future output formats.