Re: [RDA-L] Feedback on RDA

[Marjorie Bloss]

Bernhard:

I appreciate your comments -- educating me and making me think.  Thank you.

Marjorie
Marjorie E. Bloss
2827 West Gregory Street
Chicago, IL 60625
USA
1-773-878-4008
1-773-519-4009 (mobile)
marjorie_bl...@msn.com


----- Original Message ----- 
From: "Bernhard Eversberg" <e...@biblio.tu-bs.de>
To: <RDA-L@LISTSERV.LAC-BAC.GC.CA>
Sent: Wednesday, September 01, 2010 9:07 AM
Subject: Re: [RDA-L] Feedback on RDA


> Marjorie Bloss wrote:
> >
> > Regarding vendor preparation for RDA, it would have been difficult to
> > develop a system to accommodate RDA out of the box when RDA wasn't 
> > available
> > until June 23rd of this year.  However it would indeed have been 
> > possible
> > for ILS vendors to redesign their systems to support relational 
> > databases
> > perhaps even using the FRBR/FRAD conceptual models as their basis.
> >
> "Relational databases" is an all too common misunderstanding here. The
> term does not indicate that these engines are particularly well equipped
> to map relations as FRBR has them in mind. They are not. "Relational"
> stems from mathematical concepts of set theory, not more. A "relation",
> in the technical sense of the term "relational database", means nothing
> but a "subset" of a table. It does not denote the idea RDA (or FRBR)
> has in mind when saying "relation" and meaning a link between entities.
> Or, an RDBS is not based on the entity-relationship idea.
>
> What we need are *object oriented* databases. These have less
> difficulties with mapping entities, and relations between them, as RDA
> understands these matters.
> However, there's no standardization of object oriented database
> structures or concepts. For RDBS, there is SQL as a near-universal
> language for queries and operations on data, but there is no
> such thing for the OO world. This means it would be more difficult
> to construct object oriented database schemas that would be portable
> between systems.
> In reality, RDBS are very often the lower level engines in library
> applications, but the R in them is not actually used to a large
> extent. Rather, there is always a very substantial layer of software
> above it, and that layer is then mostly strictly proprietary.
>
> In short, it doesn't make a lot of sense to invoke "relational
> databases" when talking about RDA implementation. Just "databases" is
> enough, or if RDA "relations" are to be emphasized, one may talk about
> "entity-relationship models for databases".
>
> B.Eversberg
>