[panda17]

Regarding the "industry term", search:

   site:oracle.com "alternate key"

   site:microsoft.com "alternate key"

   site:ibm.com "alternate key"

[dspillett]

"defined standard" !== "industry term", though I accept your point that it appears to be more common than I was thinking.

IIRC it wasn't introduced to me when learning databases academically which I was assuming to be a standards compliant environment, but that was quite some years ago so I may or may not R C...