On Sun, Jan 26, 2003 at 12:29:12 +1000,
jack <[EMAIL PROTECTED]> wrote:
>
> I try use uique instead of primary key. And it works, it allows null values.
> Is there any other difference between primary key and unique?
I believe that the primary key is the default key for foreign key references
i
TECTED]>
Sent: Saturday, January 25, 2003 1:14 AM
Subject: Re: [SQL] quastions about primary key
> On Fri, 24 Jan 2003, jack wrote:
>
> > Is that possible to have a two columns primary key on a table with null
> > value on second column?
>
> No, because primary key i
On Fri, 24 Jan 2003, jack wrote:
> Is that possible to have a two columns primary key on a table with null
> value on second column?
No, because primary key implies not null on all columns involved
(technically I think it's that a non-deferrable primary key implies
not null on all columns involve
jack wrote:
Is that possible to have a two columns primary key on a table with null
value on second column?
Jack
Probably not, because (1,2,null,null) is unique for postresql.
Watch discussion on mailing list
about unique indexes (on which primary key is based) several days ago.
Regards,
Tomasz
