Re: [HACKERS] Fwd: Joins and links
От | Bruce Momjian |
---|---|
Тема | Re: [HACKERS] Fwd: Joins and links |
Дата | |
Msg-id | 199907072045.QAA10190@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [HACKERS] Fwd: Joins and links (Bob Devine <devine@cs.utah.edu>) |
Список | pgsql-hackers |
> Leon <leon@udmnet.ru> wrote: > > Earlier I proposed that links should be of type similar to tid, > > so inserts should be fed with values of tid. But this requires > > intermediate step, so there can be a function which takes primary > > key and returns tid, or as you say a function > > last_touched('other_table_name') - this seems the best choice. > > Beware of adding special purpose hard-links as a way to > skip the run-time value comparisons. A link looks attractive > but it really only works for one-to-one relationships > (any multi-way relationships would require a list of links > to follow) and a link has all of the overhead that a > foreign key requires. > > As somone who has developed several commercial dbms systems, > I would discourage doing a special "link" type. There are > other ways to gain performance -- de-normalize your tables > if you are doing mainly reads; carefully check your storage > layout; and, of course, buy more RAM ;-) Good to see you around Bob. This guy does know what he is talking about. -- Bruce Momjian | http://www.op.net/~candle maillist@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026
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