Skip site navigation (1) Skip section navigation (2)

Re: Re: Changing the default value of an inherited column

From: "Oliver Elphick" <olly(at)lfix(dot)co(dot)uk>
To: Peter Eisentraut <peter_e(at)gmx(dot)net>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Re: Changing the default value of an inherited column
Date: 2001-03-29 13:29:38
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
Peter Eisentraut wrote:
  >Tom Lane writes:
  >> It seems that in pre-7.0 Postgres, this works:
  >> create table one(id int default 1, descr text);
  >> create table two(id int default 2, tag text) inherits (one);
  >> with the net effect that table "two" has just one "id" column with
  >> default value 2.
  >Although the liberty to do anything you want seems appealing at first, I
  >would think that allowing this is not correct from an OO point of view.

I don't agree; this is equivalent to redefinition of a feature (=method) in
a descendant class, which is perfectly acceptable so long as the feature's
signature (equivalent to column type) remains unchanged.

Oliver Elphick                                Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight                    
PGP: 1024R/32B8FAA1: 97 EA 1D 47 72 3F 28 47  6B 7E 39 CC 56 E4 C1 47
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839  932A 614D 4C34 3E1D 0C1C
     "Trust in the Lord with all your heart and lean not on 
      your own understanding; in all your ways acknowledge  
      him, and he will direct your paths."  Proverbs 3:5,6  


pgsql-hackers by date

Next:From: Jeroen EitjesDate: 2001-03-29 13:30:37
Subject: Problem with group by in conjuction with Views
Previous:From: Oliver ElphickDate: 2001-03-29 13:27:03
Subject: Re: Changing the default value of an inherited column

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group