Re: Separate PK in Jxn Tbl?

From: David Cressey <>
Date: Mon, 28 Jan 2008 14:07:39 GMT
Message-ID: <Lklnj.800$hr6.781_at_trndny04>

"-CELKO-" <> wrote in message
> >> Does a bottle of Gin have a serial no? I am too poor to buy 2 at a time
to see if there is a different number Ah! <<
> In the US, you get a UPC/EAN code and then a batch number with booze.
> The closest thing to a serial number is your cash register receipt.

This is the "cat food problem" in a nutshell. (Or, in this discussion, the "gin bottle" problem.)
The problem has been known as the "cat food" problem for years and years.

Items on a cash register tape represent entities with no identity at the individual level, only at the batch or product level. You therefore can't tell whether two bottles of gin were checked out, or whether one bottle was scanned twice. Received on Mon Jan 28 2008 - 15:07:39 CET

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