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?
Jack ----- Original Message ----- From: "Stephan Szabo" <[EMAIL PROTECTED]> To: "jack" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> 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 implies not null on all columns involved > (technically I think it's that a non-deferrable primary key implies > not null on all columns involved, but we don't support deferrable ones) > > ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
