Re: A pk is *both* a physical and a logical object.

From: JOG <jog_at_cs.nott.ac.uk>
Date: Thu, 26 Jul 2007 03:23:35 -0700
Message-ID: <1185445415.561100.98380_at_o61g2000hsh.googlegroups.com>


Just as another example of what i'm on about with this construct m'larkey: Imagine the library has two copies of "harry potter and the deathly hallows". Are they the same book?

  1. If your construct is the one that uses the barcode on the sleeve as an identifier, then no, different books.
  2. If your construct is the one that uses the ISBN number as an identifier, then yes, same book.

There's no correct answer, and which you pick just depends on the application. A Loans database could use Barcodes; A library listings database could use ISBN. Received on Thu Jul 26 2007 - 12:23:35 CEST

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