I wrote in a previous post a bit about FRBR, Functional Requirements for Bibliographic Records. In the post, I mentioned that the model developed by IFLA, the International Federation of Library Associations, is a conceptual model based on entities and their relationships. FRBR sets the stage for more sinuous cataloging practices which fits better the environment in which information now exists.
In the FRBR conceptual model, the term ”entities” is used to name artifacts, or characteristics about artifacts that should be cataloged. Three groups of entities are described and are categorized in what FRBR calls “entity groups.” Group 1 entities are works, expressions, manifestations, and items. Group 1 entities are the backbone of FRBR’s conceptual model and understanding them is the key to understanding this entity-relationship model for cataloging. FRBR makes a clear distinction among the four types of entities in this group. According to IFLA, the types of entities in Group 1 are defined as such:
- Work is a “distinct intellectual or artistic creation.”
- Expression is “the specific intellectual or artistic form that a work takes each time it is realized.'”
- Manifestation is “the physical embodiment of an expression of a work.” As an entity, manifestation represents all the physical objects that bear the same characteristics in respect to both intellectual content and physical form.
- Item is “a single exemplar of a manifestation.” The entity defined as item is a concrete entity.
Once these entities in Group 1 are clearly distinguished from one another, relationships can be established among entities. Different types of relationships include equivalent relationships, derivative relationships, and descriptive ones. The ability for catalogers to establish relationships between entities is what increases the ability for end-users to “flow” between information artifacts on the Internet.
For an informative introduction to FRBR/RDA, please see a very informative webcast by Barbara Tillet, chief of the Policy and Standards Division, Acquisitions and Bibliographic Access Directorate at the Library of Congress at http://www.loc.gov/today/cyberlc/feature_wdesc.php?rec=4320