There was a discussion on the mailing list about the reasons of 942c. See this thread : https://lists.katipo.co.nz/pipermail/koha/2021-October/056838.html >Good afternoon, > >I recall reading (in the Koha manual?) the explanation for why it is >advantageous to define Koha item type in the bib 942 field. I believe it >has to do with exporting records, or the scope of records that is included >when doing some type of report? I'm trying to locate that information >again, but can't find it for the life of me. > >Does this seem familiar to anyone? Thanks. > > >Tasha Bales ------------ >I can't find the information right now, though I know I've seen it somewhere. >My understanding is when importing a MARC record, 942$c is treated as the >item type in the bibliographic record, and 952$y is the item type >for the item record (assuming a 952 holding field was present). > >I have also observed that when you create a new item record from an >existing bib record, 942$c gets copied into the new item's type. So >it's helpful to make sure that the item type in the bib record was set >correctly when it was created (or imported). > >This wiki page talks about 952, but not 942: > >https://wiki.koha-community.org/wiki/Holdings_data_fields_(9xx) > >I'm sure someone more knowledgeable can correct this if I'm wrong. -------------------- >942$c - defines the type of material the bibliographic record represents, >sort of like it's GMD (general material description). Has no bearing on >circulation of material. Stored as marcxml in biblio_metadata. > >952$y - defines the item-level item, and is used mandatorily for Koha's >circulation rules which work as a permutation of (a) branchcodes (b) patron >categories and (c) item-level item types. Stored as itype column in items >table. > >Hope this helps >Indranil --------------------- >952$y is mandatory for circulation IF item-level_itypes is set to "specific >item". Otherwise, 942$c is used as the item type for circulation. > >Another thing that I have observed about 942$c is that it is indexed for the >search in the same way as 952$y. So if you have records without items (for >journal articles, websites or ebooks for example), these will still be >searchable through the item type filter. > >Also, if 942$c and 952$y are not the same in one record (for example, 942$c is >Book and 952$y is Reference), they will show in the results of a search for >either type.
This was done a while ago. https://koha-community.org/manual/23.05/en/html/cataloging.html#c-koha-item-type