| From: | Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl> |
|---|---|
| To: | Fernando San Martín Woerner <snmartin(at)galilea(dot)cl> |
| Cc: | pgsql-es-ayuda(at)postgresql(dot)org |
| Subject: | Re: Restriccion condicional |
| Date: | 2005-03-30 21:39:06 |
| Message-ID: | 20050330213906.GB32752@dcc.uchile.cl |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
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| Lists: | pgsql-es-ayuda |
On Wed, Mar 30, 2005 at 05:16:01PM -0400, Fernando San Martín Woerner wrote:
> Es posible colocar una restriccion condicional en un campo, algo asi
> como tener una llave foranea en un campo, pero ademas permitir que sea
> nulo, es decir, que la llave foranea se verifique solo para los
> registros con valores no nulos.
Las llaves foraneas per se no exigen que los campos sean no nulos ...
--
Alvaro Herrera (<alvherre[(at)]dcc(dot)uchile(dot)cl>)
Essentially, you're proposing Kevlar shoes as a solution for the problem
that you want to walk around carrying a loaded gun aimed at your foot.
(Tom Lane)
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