Re: [PERFORM] typoed column name, but postgres didn't grump
От | Jon Nelson |
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Тема | Re: [PERFORM] typoed column name, but postgres didn't grump |
Дата | |
Msg-id | AANLkTikS1ne-VdEwKNp1FqWNhxF=84cXrL1P_zJYaie=@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: [PERFORM] typoed column name, but postgres didn't grump ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>) |
Список | pgsql-bugs |
On Tue, Nov 2, 2010 at 4:34 PM, Kevin Grittner <Kevin.Grittner@wicourts.gov> wrote: > Jon Nelson <jnelson+pgsql@jamponi.net> wrote: > >> If I saw this behavior ( a.b also meaning b(a) ) in another SQL >> engine, I would consider it a thoroughly unintuitive wart > > I think the main reason it has been kept is the converse -- if you > define a function "b" which takes record "a" as its only parameter, > you have effectively created a "generated column" on any relation > using record type "a". =C2=A0Kind of. =C2=A0It won't show up in the displ= ay of > the relation's structure or in a SELECT *, and you can't use it in > an unqualified reference; but you can use a.b to reference it, which > can be convenient. Aha. I think I understand, now. I also read up on CAST behavior changes between 8.1 and 8.4 (what I'm using), and I found section 34.4.2 "SQL Functions on Composite Types" quite useful. Thanks! --=20 Jon
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