Question on functional dependency
From: G.L. <datapro01_at_yahoo.com>
Date: 21 Sep 2004 17:26:34 -0700
Message-ID: <dbe53197.0409211626.2f4a00bb_at_posting.google.com>
I am reading the following:
Date: 21 Sep 2004 17:26:34 -0700
Message-ID: <dbe53197.0409211626.2f4a00bb_at_posting.google.com>
I am reading the following:
In a functional dependency X --> Y
the value of Y is *determined* by the X component.
and the value of X uniquely determines the value of Y.
Then I read
It is NOT true to say:
" Since X functionally determines Y, if we know X we know Y."
or
"If X identifies Y then X identifies Y"
(University of Virginia slide)
I'm not clear on how X can uniquely determine Y but not functionally
determine or identify
Y
Semantics? Received on Wed Sep 22 2004 - 02:26:34 CEST