Monday, July 20, 2009

Yee: Questions 12-13

[This entire thread has been combined on the futurelib wiki. Please add your comments and ideas there.]

Question 12
How do we document record display decisions?
In a sense we've covered this in the answers to other questions, but to reiterate, in addition to the data elements (called "properties" in RDF) you will need to develop one or more record formats. The record formats will provide the application with the information that is needed to produce the desired displays. I'm assuming that most display rules will be implemented in the application, but I'd be interested in hearing other ideas.

Question 13
Can all bibliographic data be reduced to either a class or a property with a finite list of values?

The answer to this is "no," but I think there's a misunderstanding here about the RDF "class." Table 2 on page 64 of Yee's article equates the RDFS "Class" with RDF "Subject" and I don't think that this is correct. As I understand Class in RDF it has a function somewhat like abstract classes in object-oriented programming: it essentially is the umbrella for a group of like things, but itself never has an actual value. Think of classes as the upper levels of a hierarchy where only the bottom elements actually are filled in with real "stuff." In the Dublin Core Metadata Elements there is a class called Agent. Particular properties like rightsHolder or creator are members of the Agent class. Agent itself isn't a property, it's an organizing feature.

That said, and I can't claim I understand it fully, I'm still not sure if the FRBR entities work as classes. In some cases, like with Person, it seems to work, but in others, like WEMI, I'm less sure.

Back to answering the question: I think we'll have the following types of properties in our library metadata:

  1. plain strings, like the transcribed title or a note

  2. formatted strings, like dates

  3. controlled lists of values, like language lists or media type lists

Then we have one other type of data, and that is where we select a display form from what today we call an "authority record." This is often considered the same as #3 in the above list, but I think there is a significant difference because an authority record is more than a term in a list: it is a rich information resource of its own. This harks back to Yee's question #5 about using cross references in authority control. Yee asks: "how will we design our systems to take advantage of the richness of authority control?" while my question is "how can we design authority control so that systems can make use of it?"

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