wrote: On Tue, Aug 28, 2007 at 12:47:45PM +0100, Sebastian Ritter wrote:=20 > > The update/message format is exactly the same for both. Should I make = two > > different tables: > > one table with extra columns : is_client, client_id, service_id, = where > > either client_id or service_id would be null depending on the = is_client=20 > > boolean? Is the rest of the data the same? If so, then one table is right. If not, then more than one table. In either case, I really hate the idea of two columns, one of which is always null. But if you're=20 going to do that, make sure you add a CHECK constraint where !(col1 IS NULL and col2 IS NULL). A -- Andrew Sullivan | ajs@crankycanuck.ca=20 I remember when computers were frustrating because they *did* exactly = what=20 you told them to. That actually seems sort of quaint now. --J.D. Baldwin ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ?=20 http://www.postgresql.org/docs/faq=20 --=__Part5B7CC495.0__= Content-Type: text/html; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Description: HTML

<quote>Im using Django as my Object relational Mapper so im = pretty sure I can not add a constraint such as ...</quote>

Then you should seriously consider changing your mapper.

>&g= t;> "Sebastian Ritter" <ritter.sebastian@gmail.com> 2007-08-28 = 16:37 >>>
Thanks for the information.

Both tables would = be exactly sames apart from the foreign key relation to clients or = services. I agree that it seems strange to have one column that is always = null. Im using Django as my Object relational Mapper so im pretty sure I = can not add a constraint such as : CHECK constraint where !(col1
IS = NULL and col2 IS NULL).

Another factor ive been considering is that = one of the fields in this table(s) definition(s) is free flowing text = which could potentially become very large. Should I take this in to =
consideration when deciding whether to split the tables? In terms of = searching speed that is.

Kindest regards.
Sebastian

On 8/28/07, Andr= ew Sullivan <ajs@crankycanuck= .ca> wrote:

On Tue, Aug 28, = 2007 at 12:47:45PM +0100, Sebastian Ritter wrote:
> > The = update/message format is exactly the same for both. Should I make = two
> > different tables:

> >   one table = with extra columns : is_client, client_id, service_id, where
> > = either client_id or service_id would be null depending on the is_client =
> > boolean?

Is the rest of the data the same?  = If so, then one table is right.
If not, then more than one table. &= nbsp;In either case, I really hate the
idea of two columns, one of = which is always null.  But if you're
going to do that, make = sure you add a CHECK constraint where !(col1
IS NULL and col2 IS = NULL).

A

--
Andrew Sullivan  | ajs@crankycanuck.ca
I remember when computers = were frustrating because they *did* exactly what
you told them = to.  That actually seems sort of quaint now.
   = ;            &n= bsp;--J.D. Baldwin

---------------------------(end of broadcast)----= -----------------------
TIP 3: Have you checked our extensive FAQ? =

           &= nbsp;   http://www= .postgresql.org/docs/faq

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