[Koha] Unique item fields

[Lenora Oftedahl]

Some of you may remember that I asked a while back about where you set MARC fields to have unique entries, as in the case of barcodes.  The setting is in Acquisitions system preferences in 3.18.  Still not sure where that's found in 3.06 anymore.    
 
In 3.18, the default is set to barcode with the option to add more fields separated by spaces.  So, I've added notes from the biblio table.  Is this going to break anything?  Does anyone else have more than one unique entry field?  I'm testing now and will report results, but thought if someone else has already tested, I might save some time.
 
Thanx.
Lenora
StreamNet Regional Library
Columbia River Inter-Tribal Fish Commission