| From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
|---|---|
| To: | Rich Shepard <rshepard(at)appl-ecosys(dot)com> |
| Cc: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: DDL issue |
| Date: | 2024-09-12 23:32:25 |
| Message-ID: | CAKFQuwahuUyPAqG2hVi=uzVdRdU-jMmQ2eZizAKAxr=s_iVVDw@mail.gmail.com |
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| Lists: | pgsql-general |
On Thursday, September 12, 2024, Rich Shepard <rshepard(at)appl-ecosys(dot)com>
wrote:
> I have one name in the people table who owns 5 different dairies with three
> different phone numbers, but all 5 have the the same email address.
>
> The five dairies each has its own name and location while the people table
> has five rows with the same last and first names and email address.
>
> Is there a way to have only one entry for the owner in the people table
> while related to five different company names? In some industries, such as
> dairy farms, this is not an unusual situation.
>
Read up on “many-to-many” data models. In SQL they involve a linking
table, one row per bidirectional edge, in addition to the two node tables.
David J.
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