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Newsgroups: microsoft.public.sqlserver.programming
Date: Wed, 12 Aug 2015 18:26:13 -0700 (PDT)
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Subject: Re: Unique Constraint Based on Dual GUID
From: --CELKO-- <jcelko212@earthlink.net>
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Xref: csiph.com microsoft.public.sqlserver.programming:31272

You missed my point! GUIDs are not for keys; they are locators for external=
 global resources. This guy wants to use them for pointers like we did in t=
he 1970'd network databases.=20

If you use an actual compound key (a,b), then either they are drawn from tw=
o different domains that are independent (longitude, latitude), two differe=
nt domains that are dependent (clothing size, colors), or the same domain (=
first color and second color). In the final case, the constraint (a < b) pr=
events (b,a), (a,a), and (b,b) Which means that the two-tone clothing item =
is only shown one way and really has two tones to it.