On 24/09/2012 16:49, Brenndorfer, Thomas wrote:
RDA has an optional addition: relationship designators
AACR2 has an optional addition: designation of function (AACR2 21.0D1)
The primary difference is that in RDA all relationships are found in the list of designators, even those not in the AACR2 21.0D1 list.
What is “broken” now is the myriad conventions in AACR2/MARC for declaring relationships, whether it conveyed by a tag number, indicator value, subfield encoding, or $w code in authority references—not just $e or $i codes.
RDA puts them all in a list, and treats them all as functionally the same. That’s an excellent approach, because it means we don’t have to be beholden to the myriad MARC conventions as the primary basis for declaring what the relationship is, and to say what is possible or not because it’s just too hard to add to MARC.
I hope that helps in your struggles to understand RDA.
Perhaps I am not making myself clear. I shall assume you have not listened to the podcast because your statements are beside the point here. Being able to add new codes, and making them standardized, is elementary, but doing this has consequences that apparently not everyone understands, and that is what my podcast is about.
First, it is important to approach this issue not as a cataloger and not as an IT person. It is absolutely necessary to approach this as a non-librarian member of the public who wants to use the catalog to find the materials in the collection.
Now, my example is: I am a user who knows practically nothing about a catalog. I am interested in John Huston and I want to see what movies the local collection has that he directed. I see an option to search “film directors” in the catalog. The result will contain only those records that contain John Huston’s heading (or his URI) where he is coded as “film director”.
In the meantime, since RDA has begun, our library has added only a single DVD Blue-ray for “Moby Dick” and therefore, when the search is for “John Huston” as film director it can only retrieve the Blue-ray for Moby Dick. Yet, in my collection is every movie John Huston ever directed but they were cataloged earlier and do not have the code for “film director”.
Therefore, from the searcher’s standpoint, the library has only one movie directed by John Huston. The access has decreased. To know that there are more becomes highly complex for the searcher.
In turn, I hope this helps you understand the importance of consistency in library catalogs and that to break that consistency has consequences, some of which may be difficult to foresee even for catalogers.