From: | Alban Hertroys <alban(at)magproductions(dot)nl> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Vector type (Re: challenging constraint situation - |
Date: | 2006-05-26 14:04:27 |
Message-ID: | 44770AEB.301@magproductions.nl |
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Lists: | pgsql-general |
Tom Lane wrote:
> Alban Hertroys <alban(at)magproductions(dot)nl> writes:
>>With what I have in mind, both overlap and equality would violate the
>>unique constraint. I don't quite see why someone'd want to forbid
>>overlap but to allow equality; isn't not allowing equality the whole
>>point of a unique constraint?
>
> You're missing the point. Letting "~" represent the operator that
> tests for interval-overlap, we can have
> A --------------
> B ------------------
I'd say "unique constraint violation" right here (provided there's a
unique constraint on this column, of course). The order in which these
are inserted/updated doesn't seem to matter either. I'm afraid I'm still
missing the point... or maybe I'm not wrong???
> C ----------------
> so that A ~ B and B ~ C but not A ~ C. This is too much unlike normal
> equality for a btree to work with "~" as the "equality" operator.
--
Alban Hertroys
alban(at)magproductions(dot)nl
magproductions b.v.
T: ++31(0)534346874
F: ++31(0)534346876
M:
I: www.magproductions.nl
A: Postbus 416
7500 AK Enschede
// Integrate Your World //
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