No, I'm not sending libraries to the emergency room, although there are days when I feel like we're at that point. The ER in the title refers to Entity-Relationship, a way to look at data that emphasizes the general viewpoint that there are things, and those things exist in relation to each other.
In one sense, this is what we have done for over a century with our library data. The bibliographic records that we create have in them many relationships: Person authored Book; Publishing House published Book; Book is in Series; Book has Topics. Those relationships are implicit in our records, but the data isn't formatted in an entity-relationship model. Our records, instead, talk about the relationships but don't make it easy to give the various entities their own existence. So we create a record that contains:
Place, publisher, date
The record represents all of the information about the book, but there is no record that represents all of the information about the author, or all of the information about the publisher, etc. Instead, those "entities" are buried in bibliographic records scattered throughout the file.
An E-R model would give each of these entities an identity on which you could hang information about the entity.
OK, I can't draw worth beans. But basically the idea is that authors, subjects, publishers, topics, all become entries in their own right. This means that you can add information to the author record or the series record, because they have their own place in the design. It also makes it easy to look at your data from many different points of view, while still retaining all of the richness of the relationships. So from the point of view of the person who is the illustrator in the book above, the bibliographic world may look like this:
This type of model is expressed in FRBR, but the E-R aspect of FRBR does not seem to be incorporated into RDA as it stands today. Instead, RDA appears to be aimed at creating the same flat structure that we have in library data today.
If you take a look at the OpenLibrary you will see that books get a page that is about the book, and authors get a separate page that is about the author. This is very simple, but it is also very important. It means that the catalog is no longer just a list of books with authors but can become a rich source of information about authors. You can add bios for authors, link to web sites about the author, launch a discussion group about a favorite author. Because the author is an entity, not just a data element in a record about the book, it becomes a potentially active part of your information system.
In the future, I hope that we can give life to many more entities in the OpenLibrary, and also that we can give them meaningful relationships between each other. This would mean taking a semantic web approach to library data. I don't have a clear picture of where we'll end up, but I'm glad that folks there are interested in experimenting. If you've already thought this through or have ideas in this direction, please step forward. I'd love to hear from you.