Re: [SQL] Design Question - Mailing list pgsql-sql

Hi Rich,

I think that if you :
- create one table "brokers" with the broker's name (let's call that
broker_name) and a unique id (just in case two show up with the same
name, there are many Smiths, isn't it ?). The ID could be an integer
up-counting number (1 for the first, 2 for the second, ...), let's call
that field broker_id.

-create a second table "locations" which contains all nessecary fields
for a certain location of a certain broker (street, mailbox, city,
state, ..) AND a field broker_id, which should have the same integer as
the broker_id of the broker's table.

Now the name of the broker only appears once in the brokers table. So
even if the broker's company should be called "John Smiths Absolutely
Marvellous and undoubtedly honest stock trade company", and have 50
houses all over the states, this name only takes disk space once. And
that's one of the objectives of relational databases : limit the
occurance of extensive and repeating data by writing it once, and then
pointing to it, instead of writing it again and again.

You should take care, however, that the datatype for broker_id is the
same in both tables ! So, if you use an integer for it in the brokers
table, then use an integer type in the locations table as well !

Hope this explains something :-) It's only the tip of the veil, of
course. If this interrests you, you should really buy a book on
relational databases.

Toi,
Walter De Moudt
Rich Shepard wrote:
> 
> On Sat, 27 Nov 1999, Andy Lewis wrote:
> 
> > Lets say that I have a DB that I am using to save address info on
> > different brokers. Broker name, address, city, state, zip
> >
> > Some brokers have representation in different states.
> >
> > How would I be able to save that info so that it can be later selected by
> > users looking for a broker in a certain state(s)?
> >
> > What type of field/table/DB could I save that in for easy reference?
> 
> Andy,
> 
>   I suggest that you buy (or borrow from a library) a book on relational
> data base design. To give you the simple answer to your question: have one
> table for the broker's name and identification and a separate table for
> their addresses. It's called a many-to-one structure and is created by
> normalizing the data.
> 
> Rich
> 
> Dr. Richard B. Shepard, President
> 
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