Re: null foreign key column - Mailing list pgsql-sql
| From | Vernon Wu |
|---|---|
| Subject | Re: null foreign key column |
| Date | |
| Msg-id | FEY83IG42SQA7EB94TR71LGNMVUWSUO.3e4acc1b@kimiko Whole thread Raw |
| In response to | Re: null foreign key column (Dmitry Tkach <dmitry@openratings.com>) |
| Responses |
Re: null foreign key column
Re: null foreign key column |
| List | pgsql-sql |
12/02/2003 2:24:49 PM, Dmitry Tkach <dmitry@openratings.com> wrote: >You don't want it to be serial - just make it 'person_id in' Any reasons? > >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> </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>= >> </DIV> >> <DIV><FONT face=3DArial size=3D2>create table event<BR>(<BR> &nb= >> sp;=20 >> event_id &= >> nbsp; =20 >> serial &nb= >> sp; =20 >> not null,<BR> event_description &n= >> bsp;=20 >> char(255) = >> =20 >> ,<BR> =20 >> person_id = >> =20 >> serial &nb= >> sp; =20 >> ,<BR> primary key (event_id),<BR> forei= >> gn=20 >> key (person_id)<BR> references pe= >> rson=20 >> (person_id)<BR>);</FONT></DIV> >> <DIV><FONT face=3DArial size=3D2></FONT> </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-- >> > > >---------------------------(end of broadcast)--------------------------- >TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) >