Re: Polymorphic delete help needed

On Thu, Jul 05, 2007 at 09:56:12PM -0500, Perry Smith wrote:

I am doing a project using Ruby On Rails with PostgreSQL as the  

database.  I have not seen the term polymorphic used with databases  

except with Rails so I will quickly describe it.

You have now :)

http://archives.postgresql.org/sfpug/2005-04/msg00022.php

Instead of holding just an id as a foreign key, the record holds a  

"type" field which is a string and an id.  The string is the name of  

the table to which the id applies.  (That is slightly simplified).

This is brittle by nature.  The above link sketches out a way to make

it stable.  If you have questions, ask :)

The first problem

of many ;)

[other stuff snipped]

that creates is it makes it hard to do a constraint  

on the name/id pair.

Let PostgreSQL work *for* you instead of picking a fight with it and

then piling on heaps of unnecessary code.