[Koha] Reason to define Koha item type in 942

[Mark Alexander]

Excerpts from Bales (US), Tasha R's message of 2021-10-14 19:13:14 +0000:
> 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.

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.

-- 
I am unconditionally guaranteed to be
full of defects. --Ashleigh Brilliant