You are viewing a plain text version of this content. The canonical link for it is here.

Posted to derby-user@db.apache.org by "Biene_Majo@yahoo.de" <Bi...@yahoo.de> on 2011/11/10 02:04:24 UTC

Unique Column with null values

Hi,

is there a way to mix an unique column with null values. So that i have an  
column where only unique values are allowed with the exception of multiple  
null values.

Greetings,

Biene_Maja

Re: Unique Column with null values

Posted by Bryan Pendleton <bp...@gmail.com>.

> is there a way to mix an unique column with null values. So that i have an column where only unique values are allowed with the
> exception of multiple null values.

Yes.

Since Derby 10.4, that is the way that Derby's table-level UNIQUE constraints
have worked. See:

http://db.apache.org/derby/docs/10.8/ref/rrefsqlj13590.html

thanks,

bryan