| From: | Richard Broersma Jr <rabroersma(at)yahoo(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Alban Hertroys <alban(at)magproductions(dot)nl> |
| Cc: | Robert Haas <Robert(dot)Haas(at)dyntek(dot)com>, David Fetter <david(at)fetter(dot)org>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: complex referential integrity constraints |
| Date: | 2007-02-23 23:58:57 |
| Message-ID: | 118382.45919.qm@web31803.mail.mud.yahoo.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
to attack eachother.
>
> Depending on what you're modelling, even this could be too simple -- for
> example, while a single wolf is unlikely to attack a lion, a pack of
> wolves have a lot more probability of doing so.
>
> Do you keep packs of wolves in your barn? If so, watch your lions.
Well from the previous thread that discussed the use of the <animal> table and sub-set tables
<prey> and <preditor>, if a preditor can attach a prey item or preditor item, then a table
relation only needs to be created between <preditor> and <animal>. This way only preditors can
attack, but they can attach any other animal preditor or prey.
Regards,
Richard Broersma Jr.
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