Re: Foreign key constraint accepted even when not same
От | Bruce Momjian |
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Тема | Re: Foreign key constraint accepted even when not same |
Дата | |
Msg-id | 200309250208.h8P28md27643@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: Foreign key constraint accepted even when not same (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Foreign key constraint accepted even when not same
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Список | pgsql-general |
Tom Lane wrote: > Stephan Szabo <sszabo@megazone.bigpanda.com> writes: > > On Mon, 22 Sep 2003, Jean-Christian Imbeault wrote: > >> Is it right for postgres to accept a foreign key constraint when the > >> type of the field is not the same as that of the foreign key? > > > IIRC in SQL92 it's said that they need to be the same type, but in SQL99 > > it says that the two types must be comparable. We basically implement the > > latter, basically using the existance of a usable equality operator as the > > determination of comparable. > > Note however that performance may be poor with a cross-type foreign key > reference, if the planner is unable to figure out how to use an index > for the check queries. Didn't we agree to throw a NOTICE in cases of a mismatch? (I think Peter agreed to a NOTICE but not a WARNING) Is that completed? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
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