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Re: Unique index vs. unique constraint

From: <adholaki_at_my-deja.com>
Date: Tue, 14 Sep 1999 17:12:18 GMT
Message-ID: <7rlvla$qsq$1@nnrp1.deja.com>


What is the SQL syntax for inserting a value into a column with a unique constraint/ index?

ie.

INSERT into Company (id, name, address)

VALUES (56, someCompany, 555 malibu dr.)

here, the id column has a unique constraint and is not linked to any other table. the above statement results in a parent key violated or some other error.

the keyword "nextval" was mentioned, but i don't have any details on this.

thanks

In article <37CD0E1C.78F9_at_yahoo.com>,
  connor_mcdonald_at_yahoo.com wrote:
> Richard Gaston wrote:
> >
> > I think unique constraints are implemented as unique indexes in
oracle.
> > Oracle will create a unique index for the column(s) you declare
unique in a
> > constraint. So apparently, there's no real difference between the
two.
> >
> > As to why you'd prefer one over the other, I don't know. Taste?
> >
> > Michael Hjorth <michael_hjorth_at_my-deja.com> wrote in message
> > news:7q2vo5$c0g$1_at_nnrp1.deja.com...
> > > What is the functional difference between a unique index and a
unique
> > > constraint?
> > > I know the latter has a constraint as well as the index, but
apparently
> > > it enforces the same restrictions on the database as the unique
index.
> > > Or did I get it wrong?
> > > Why would I prefer one over the other in a particular case?
> > >
> > > Thank you for any comments.
> > >
> > > Michael.
> > >
> > >
> > > Sent via Deja.com http://www.deja.com/
> > > Share what you know. Learn what you don't.
>
> It is possible to implement a unique constraint with a NON unique
index
> in 8.1, thus making them different...
>
> Also with unique constraints you can make them deferrable and other
nice
> things that cannot be done with a unique index.
>
> Cheers
>
> --
> ===========================================
> Connor McDonald
> "These views mine, no-one elses etc etc"
> connor_mcdonald_at_yahoo.com
>
> "Some days you're the pigeon, and some days you're the statue."
>

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't. Received on Tue Sep 14 1999 - 12:12:18 CDT

Original text of this message

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