Re: WIP: generalized index constraints
От | tomas@tuxteam.de |
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Тема | Re: WIP: generalized index constraints |
Дата | |
Msg-id | 20090916131114.GA19820@tomas обсуждение исходный текст |
Ответ на | Re: WIP: generalized index constraints (Jeff Davis <pgsql@j-davis.com>) |
Ответы |
Re: WIP: generalized index constraints
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Список | pgsql-hackers |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tue, Sep 15, 2009 at 10:28:28AM -0700, Jeff Davis wrote: > On Tue, 2009-09-15 at 13:16 -0400, Robert Haas wrote: > > Uhh.... so what happens if I create an index constraint using the > > +(integer, integer) operator? > > You can use any operator that has an index search strategy. Overlaps is > probably the most useful, but you could imagine other operators, like a > bi-directional containment operator (either LHS is contained in RHS, or > vice-versa). > > You can also get creative and have a "similarity" operator that > determines whether two tuples are "too similar". As long as it is > symmetric, the feature will work. One question: does the operator have to be reflexive? I.e. "A op A holds for all A"? I am thinking "proximity" or as you state above "similarity". May be this is a good metaphor, leading to a good name. Regards - -- tomás -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFKsOPyBcgs9XrR2kYRAhsUAJkBICYUMK0tDrycPbctiGF7YKI/9gCeLQzq DPyAAkMgZJFn8BZ7P8119/g= =lVz1 -----END PGP SIGNATURE-----
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