Re: Distinct types

On Fri, 2008-11-28 at 11:20 -0500, Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > Simon Riggs wrote:
> >> Shame, this was sorely needed.
> 
> > I understand, but the work required to make it work properly is too much 
> > under the commit fest spirit right now.
> 
> Personally I was wondering exactly why it's "sorely needed".  There has
> been not one field request for this functionality; in fact I'd never
> heard of the feature until Peter popped up with his patch.  I assumed he
> was simply trying to see if we could tick off another SQL feature
> checkbox with a small number of lines of code.
> 
> If it's going to take a significant amount of work then I think someone
> ought to provide an actual justification why it's worth the work.

Few thoughts: 

* Domains don't work very well in conjunction with arrays. 

* Strong typing is preferable in complex applications to avoid errors
like sum(ordinal_column). Most developers use this all the time in their
3GL code but cannot use it in SQL.

* Allows migration of code easier from places that use strange sounding
datatypes that can be mapped easily to existing datatypes.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support