Re: novice on table design

["Tony S. Wu" <tonyswu@xxxxxxx>]

actually, no, Shop, Employee, and Customer are not distinct.
in your instance they are the same type of entry.
don't distinguish them by tables, rather use a column to hold some sort 
of an ID for each type.
of course you'll end up with a table with many columns, and many of 
them will be null depending on which type an entry is.
but with this approach, you can easily associate with an address table.

Tony S. Wu
tonyswu@xxxxxxx



On May 14, 2005, at 4:49 AM, tony yau wrote:

> Hi Miguel,
>     Thanks for the reply.
>
>     the non-customer is actually a Shop, so Employee, Customer and 
> Shop are
> distinct enough to have their own tables. Now they all have an 
> Address, and
> the problem is how do I allow multiple addresses for each these 
> 'people'
> (without using
> a lookup table)
>
> tony.
>
> "Miguel Guirao" <miguel.guirao@xxxxxxxxxxxxxxx> wrote in message
> news:GFEHIFBDMNHCPDFHEJDGEEOOCDAA.miguel.guirao@xxxxxxxxxxxxxxxxxx
> > The schema of your table is wrong, is you do bnormalize it you will 
> > find
> out
> > that you need two tables for this approach.
> >
> > One table for your people and another one for the n addresses of your
> > people.
> >
> > If you keep your current schema, you will have as many rows for one 
> > person
> > as many addresses for that person you have, and you will be 
> > duplicating
> many
> > fields. So you must split your tables, one for your people and 
> > another for
> > your people's addresses.
> >
> > -----Original Message-----
> > From: tony yau [mailto:tony.yau@xxxxxxxxxxxx]
> > Sent: Viernes, 13 de Mayo de 2005 09:27 a.m.
> > To: php-db@xxxxxxxxxxxxx
> > Subject:  novice on table design
> >
> >
> >
> > Hi all,
> >
> > I have the following tables
> >
> >     Employee            Customer            non-Customer
> Address
> > ==========    ==========    =============    ==========
> >     pkey                     pkey                    pkey
> > pkey
> >     number                 type                     type
> > ...
> >     payrate                 grant                    capital
> >
> > I need to allow the three types of people to have n addresses, so I've
> added
> > a type to distinguish the 3 types of people and their respective pkey 
> > onto
> > address table.
> >
> >     Address
> > =========
> >     pkey
> >     ...
> >     type    (either Employee, Customer or non-Customer etc)
> >     fkey    (the pkey of Employee, Customer or non-Customer etc)
> >
> > I know this design looks awkward but it does have the advantage of 
> > having
> > less tables otherwise.
> > BUT somehow it doesn't feel right. Can someone points me its pros and
> cons.
> > thanks all.
> > Tony Yau
> >
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