Re: effective SELECT from child tables

On Fri, Sep 30, 2005 at 06:30:10PM -0500, Jim C. Nasby wrote:
> On Wed, Sep 28, 2005 at 07:25:46PM +0100, Simon Riggs wrote:
> > Include the Discriminator as a column in A and it will be inherited by
> > all A1, A2, A3.
> > e.g. concrete_class char(1) not null
> <snip>
> > This will add 1 byte per row in your superclass... and requires no
>
> I thought char was actually stored variable-length...? I know there's a
> type that actually acts like char does on most databases, but I can't
> remember what it is off-hand (it should be mentioned in docs 8.3...)

IIRC, this is the difference between "char" and char(1). The latter is
variable length and can store any character per current encoding, hence
the variable length. "char" on the other hand is a one byte (presumably
ASCII) character. It's used mainly in the system catalogs...
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.