So my understanding is that many ‘entries’ in a cataloging record are meant to be ‘citations’. They are meant to unambiguously identify the work cited. In the age when cataloging rules were created, what you’d do with that unambiguous citation was simply look it up in a printed or card catalog.
But the very precise rules involving ‘main entry’ and ‘uniform title’ should, I believe, allow software to unambiguously find the target of the citation in a database, if it’s there.
I am at the very beginning stages of figuring out how to do this exactly, it’s not exactly simple.
If it turns out that you can’t even do this, I’m really going to think that much of the very complicated and time-consuming cataloging rules are irrelevant in the post-card-catalog age. But we’re not there yet.
Initial signs, however, aren’t very good. Take this example from OCLC docs on 76x-78x linking fields.
The first choice for identification is the uniform title. If available, use the entire uniform title (e.g., title and qualifier) to identify the related publication. If the uniform title is unavailable, use the main entry and title proper. For example, if OCLC record number 6597310 has the following uniform title:
130 0 Monthly digest of statistics (Zimbabwe. Central Statistical Office)
It would be linked to the related publication in field 780.
780 0 0 ‡t Monthly digest of statistics (Zimbabwe. Central Statistical Office) ‡w (OCoLC)6597310
Okay, fair enough. And a referenced uniform title should indeed allow us to unambiguously identify records belonging to the cited work. But wait. That title is clearly a uniform title, it’s given in a 130.
But in the 780 example then… shouldn’t that title be in subfield ‘s’, not ‘t’? 780 subfield s is clearly documented as “uniform title”, right?
But wait, $t says: it is indeed used for title elements from a 245 or a 130. Subfield ‘u’ is only used for field 240 entered uniform titles.
So wait, when citing a work in a 780, you put a uniform title in subfield s if it’s title-main-entry, but you put it in subfield t if it’s author main entry? And when you find a title in t, there’s no way to know if it’s a uniform (controlled) title, or a transcribed (245) title?
Um. So, um. I am kinda speechless. If you’re going to spend all these expensive cataloger hours following very precise rules, wouldn’t it be sensible to make the rules result in data that can actually be interpreted to do what’s it’s supposed to do?