From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | Peter Eisentraut <peter_e(at)gmx(dot)net>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: foreign keys for array/period contains relationships |
Date: | 2010-10-25 20:10:21 |
Message-ID: | AANLkTimm9BSP-4Qb3HYtGVm8npM311YVd_Rg21dHumWf@mail.gmail.com |
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Lists: | pgsql-hackers |
2010/10/25 Robert Haas <robertmhaas(at)gmail(dot)com>:
> On Mon, Oct 25, 2010 at 3:11 PM, Peter Eisentraut <peter_e(at)gmx(dot)net> wrote:
>> Currently, foreign keys only work with the = operator (the name might be
>> different, but it needs to behave like equality). I'm thinking there
>> are other scenarios that could be useful, for example with arrays and
>> range types.
>>
>> Example #1: Foreign key side is an array, every member must match some
>> PK.
>>
>> CREATE TABLE pk (a int PRIMARKY KEY, ...);
>>
>> CREATE TABLE fk (x int[] REFERENCES pk (a), ...);
What about optimalizations and planning? This is classic sample how
don't use a arrays?
Regards
Pavel
>
> I've wished for this before when doing app dev with PG. I think it
> would be pretty neat. The other cases seem potentially useful, too,
> but especially this one.
>
> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
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