Re: [GENERAL] disjoint union types

2007-10-12 Thread Sam Mason
On Wed, Oct 10, 2007 at 12:10:10PM -0500, Erik Jones wrote: On Oct 10, 2007, at 11:42 AM, Sam Mason wrote: On Wed, Oct 10, 2007 at 05:02:36PM +0100, Ian Barber wrote: CREATE TABLE shapes ( shape_id serial PRIMARY KEY, area real not null ); CREATE TABLE circle ( radius real not null )

Re: [GENERAL] disjoint union types

2007-10-10 Thread Sam Mason
On Tue, Oct 09, 2007 at 10:30:15AM -0500, Erik Jones wrote: On Oct 9, 2007, at 9:38 AM, Sam Mason wrote: CREATE TABLE circle ( id SERIAL PRIMARY KEY, radius REAL NOT NULL ); CREATE TABLE square ( id SERIAL PRIMARY KEY, sidelen REAL NOT NULL ); CREATE TABLE shapes ( id SERIAL

Re: [GENERAL] disjoint union types

2007-10-10 Thread Ian Barber
On 10/10/07, Sam Mason [EMAIL PROTECTED] wrote: On Tue, Oct 09, 2007 at 10:30:15AM -0500, Erik Jones wrote: On Oct 9, 2007, at 9:38 AM, Sam Mason wrote: CREATE TABLE circle ( id SERIAL PRIMARY KEY, radius REAL NOT NULL ); CREATE TABLE square ( id SERIAL PRIMARY KEY, sidelen REAL NOT

Re: [GENERAL] disjoint union types

2007-10-10 Thread Sam Mason
On Wed, Oct 10, 2007 at 05:02:36PM +0100, Ian Barber wrote: I wonder if the best way to go would be to use the OO stuff. I don't see how the following is object orientated, but I'm not sure it matters much. If you had a shapes table, that had the various operations you were interested in (say

Re: [GENERAL] disjoint union types

2007-10-10 Thread Erik Jones
On Oct 10, 2007, at 11:42 AM, Sam Mason wrote: On Wed, Oct 10, 2007 at 05:02:36PM +0100, Ian Barber wrote: I wonder if the best way to go would be to use the OO stuff. I don't see how the following is object orientated, but I'm not sure it matters much. If you had a shapes table, that

[GENERAL] disjoint union types

2007-10-09 Thread Sam Mason
Hi, I was after opinions as to the best way to lay tables out to get the effect of a disjoint union type (also known as a tagged union). When I have to do this at the moment, I'm creating a structure like: CREATE TABLE circle ( id SERIAL PRIMARY KEY, radius REAL NOT NULL ); CREATE TABLE

Re: [GENERAL] disjoint union types

2007-10-09 Thread Erik Jones
On Oct 9, 2007, at 9:38 AM, Sam Mason wrote: Hi, I was after opinions as to the best way to lay tables out to get the effect of a disjoint union type (also known as a tagged union). When I have to do this at the moment, I'm creating a structure like: CREATE TABLE circle ( id SERIAL PRIMARY