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, like Dublin Core and FRBR. You can use these or you could populate a custom vocabulary with the relations needed in your archive. 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. You can 1) indicate whether you want to display an item's relations on its public show page; and 2) select the format of an item's relations that you'd prefer to show: prefix:localPart or label (see below under "Item Relations and RDF"). You can always reconfigure the plugin by going to the "Plugins" tab on the "Settings" page.
On the "Item Relations" tab on the main navigation you can browse the vocabularies and their properties (a more general term for relations). You can 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.
When adding or editing an item, click on the "Item Relations" tab to relate the item to another item and delete existing relations. For now you'll need the item ID of the other item to define a relation, but we plan to add a more user-friendly item selector system in a future version.
In version 1.1, users may batch relate items using the Batch Edit function for items.
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.