Foreign Key References

From: Steve Long <steven.long_at_erols.com>
Date: Wed, 11 Apr 2001 18:14:28 -0400
Message-ID: <9b2l53$f0c$1@bob.news.rcn.net>

it should be noted that the requirement a foreign key reference only a primary key is implementation specific wrt RDBMS vendors. this constraint is artificial in the formal definitions of keys.

"Bart" <Bart_at_opcomp.demon.co.uk> wrote in message news:987024225.10953.0.nnrp-14.9e985e86_at_news.demon.co.uk...
> A primary key is, by definition, the primary key to a table and a table
can
> have only one.
>
> A primary key is not an index, although is usually has an associated
index.
>
> A table can have any number of unique indexes.
>
> A foreign key can only reference a primary key.
>
> <u518615722_at_spawnkill.ip-mobilphone.net> wrote in message
> news:l.987022508.1940429687@[198.138.198.252]...
> > I searched against metalink and could not find the
> > definition of unique index, could somebody help
> > me out?
> >
> > Thanks
> >
> >
> >
> >
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Received on Wed Apr 11 2001 - 17:14:28 CDT