Re: Index to enforce non-overlapping ranges?

James Robinson <jlrobins@[EMAIL PROTECTED]
> writes:
> 	Given a table with a pair of any sort of line-segment-esqe range  
> delimiter columns, is it possible to build a unique index to enforce  
> non-overlapping ranges?

Nope, sorry.  Unique indexes enforce non-equality, but there's no way
to pretend that "overlaps" is an equality condition (hint: it's not
transitive).

I don't say that it'd be impossible to construct an index type that
could do this, but you won't get there with the pieces we have.

			regards, tom lane

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