This behavior was revealed due to a misconfiguration of Koha to MARC mappings, in which 942$c was associated with items.itype. For any record edited after the change, the value of biblioitems.itemtype was changed to NULL. The issue came to our attention when staff noticed that records' details display pages showed neither the item type image nor the item type description. However, the edit record page (somehow) continued to display its correct item type. Updating the item type on this page, despite an apparently successful save action, did not change the value of biblioitems.itemtype; it remained NULL. The behavior caused much confusion among the staff until the error was traced back to the misconfiguration. An UPDATE action on biblioitems.itemtype could restore the correct value, but a subsequent edit of the record would return the value to NULL. Correcting the Koha to MARC mapping restored proper function. Thanks for reading!
Not clear what part of that is a bug which could be fixed. I'd expect that the 'MARC bibliographic framework test' would have told you that its test of 'All item fields are in the same tag and in item tab' was failing, but automatically running that after every add or remove in 'Koha to MARC maapping' seems excessive.
Hi, Phil, and thanks for responding. Because the individual who created the misconfiguration(s) rushed in to both the test and production servers to reverse what could be reversed, I lost immediate access to whatever errors may have been revealed on that page. Once another matter gets cleared up, I will be able to restore the test server to an earlier point in time and see how it read. In any case, I don't think that the edit record page should show values that aren't really there. I was unable to determine on my own how the former value (now NULL) was being displayed or from where the interface retrieved it. That's the point at which I'd say there's a "bug": displaying information that is contrary to the stored value in the database.
Ah, I see what you mean. But that's not how Koha works. The thing you edit in the cataloging editor doesn't live in the biblio and biblioitems tables; it's a blob of MARC data in the biblio_metadata table. And "Koha to MARC mapping" would be more accurately called "MARC to Koha mapping" since it's one-way that direction: you can map a MARC field to a Koha database column so that changes to the MARC field are copied into that biblio/biblio_items/items database column, but the database column isn't mapped back to the MARC field and changes to it don't change the MARC record. So all along the editor was showing you what was in 942$c in the MARC record, but no matter how 942$c is mapped it won't show you something from biblioitems or items, only from the MARC.
Thank you for that *excellent* explanation, Phil. It's helpful information to have, especially the part about it being a one-way relationship.