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From: Dmitry Tkach <dmitry@openratings.com>
To: pgsql-sql@postgresql.org
Subject: Re: null foreign key column
Date: Wed, 12 Feb 2003 17:24:49 -0500
Message-ID: <b2ebqi$9eb$1@news.hub.org> (raw)
In-Reply-To: <000801c2d181$6c0be360$020000c0@singlarc01>
References: <000801c2d181$6c0be360$020000c0@singlarc01>

You don't want it to be serial - just make it 'person_id in'

I hope, it helps...

Dima

Arunachalam Jaisankar wrote:
> This is a multi-part message in MIME format.
> 
> ------=_NextPart_000_0005_01C2D1EE.61998D70
> Content-Type: text/plain;
> 	charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
> 
> Hi all,
> 
> I would like to have a foreign key column in my table which allows null val=
> ue also.
> But the below create table sql command doesn't accept null value for person=
> _id.
> How to do in postgres?
> 
> create table event
> (
>     event_id               serial                not null,
>     event_description      char(255)                     ,
>     person_id              serial                        ,
>     primary key (event_id),
>     foreign key  (person_id)
>        references person (person_id)
> );
> 
> regards
> Jai
> ------=_NextPart_000_0005_01C2D1EE.61998D70
> Content-Type: text/html;
> 	charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
> 
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> <HTML><HEAD>
> <META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-8859-1">
> <META content=3D"MSHTML 6.00.2800.1106" name=3DGENERATOR>
> <STYLE></STYLE>
> </HEAD>
> <BODY bgColor=3D#ffffff>
> <DIV><FONT face=3DArial size=3D2>Hi all,</FONT></DIV>
> <DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
> <DIV><FONT face=3DArial size=3D2>I would like to have a foreign key column =
> in my=20
> table which allows null value also.</FONT></DIV>
> <DIV><FONT face=3DArial size=3D2>But the below create table sql command doe=
> sn't=20
> accept null value for person_id.</FONT></DIV>
> <DIV><FONT face=3DArial size=3D2>How to do in postgres?</FONT></DIV>
> <DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial size=3D2></FONT>=
> &nbsp;</DIV>
> <DIV><FONT face=3DArial size=3D2>create table event<BR>(<BR>&nbsp;&nbsp;&nb=
> sp;=20
> event_id&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
> nbsp;&nbsp;&nbsp;=20
> serial&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
> sp;&nbsp;&nbsp;&nbsp;=20
> not null,<BR>&nbsp;&nbsp;&nbsp; event_description&nbsp;&nbsp;&nbsp;&nbsp;&n=
> bsp;=20
> char(255)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=20
> ,<BR>&nbsp;&nbsp;&nbsp;=20
> person_id&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
> &nbsp;&nbsp;=20
> serial&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
> sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=20
> ,<BR>&nbsp;&nbsp;&nbsp; primary key (event_id),<BR>&nbsp;&nbsp;&nbsp; forei=
> gn=20
> key&nbsp; (person_id)<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; references pe=
> rson=20
> (person_id)<BR>);</FONT></DIV>
> <DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
> <DIV><FONT face=3DArial size=3D2>regards</FONT></DIV>
> <DIV><FONT face=3DArial size=3D2>Jai</FONT></DIV></BODY></HTML>
> 
> ------=_NextPart_000_0005_01C2D1EE.61998D70--
> 




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