https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=41414 --- Comment #3 from Alexander Wagner <alexander.wagner@desy.de> ---
The ISBN isn't just a title.
Well, it was a bit unclear. From a data perspective the ISBN lives on the title level. Otherwise you'll have to repeat the same value for each item in a record that is associated with said title.
It represents a specific edition and format of that title.
Agree. (Ignoring some funny corner cases we have.) Still, _of the title_ is the crucial part here, IMHO. The ISBN is not a property of the item(tm), but of all items of the same specific edition, format etc. Hence it should live on a level above the item. In this regard the ISBN is IMHO like the authors, title, edition statement, extent... And IMHO that's why it's modelled that way by the cataloguing rules.
Not all items in the record are exactly alike
I think this is where we may differ. Usually, items of the same edition live on one record here. If we get identical copies they are added. I believe even unchanged reprints fall now in this category. If there is a `2nd revised edition` however, it get's a new record. In general I think your approach would require a bunch of other fields to live on the item as well. E.g. (100/700, 245,) 250, 300, thinking of works like https://pubdb.desy.de/record/383719 where the author changed at some specific point in time and later even the title changed as a reference to the original author. Still it's the same book that just got expanded in certain editions. Stuff like this most likely does not happen on a novel, though. But well, thinking of Tolkiens "Lord of the Rings" originally published in 3 books or as one large bound volume... Or it's translations even to the same language by various translators. (I admit that I'd strongly prefer either the English edition or a specific translation myself, in this case, so it would be nice if I could get that one.)
We ended up splitting our large print records from our other copies a while back
As soon as it's a new edition or something _different_ we do add a new record. (Being from a small special library: one would also cite it differently. Or to your example: the page numbers are surely different in the large prints than in the regulars.) To me it sounds a bit like you are heading for a light version of FRBR. That is, I think I understand now what you want to do. I am still unsure if your approach is the most suitable. -- You are receiving this mail because: You are the assignee for the bug. You are watching all bug changes.