Re: [PATCHES] ALTER TABLE modifications
От | Peter Eisentraut |
---|---|
Тема | Re: [PATCHES] ALTER TABLE modifications |
Дата | |
Msg-id | Pine.LNX.4.44.0311141956540.5327-100000@peter.localdomain обсуждение исходный текст |
Список | pgsql-hackers |
Hannu Krosing writes: > > AFAICT, this patch does not buy us anything at all. It's just a different > > spelling of existing functionality. We have never done that before. > > what about DROP COLUMN - this is also just a different spelling for > > SELECT INTO, migrate all constraints, DROP OLD TABLE, RENAME. No, because DROP COLUMN preserves dependent objects. > > We cannot possibly leave this patch as is. People expect in-place column > > changes. > > Does SQL spec even require that SELECT * always returns columns in the > same order ? Yes: b) Otherwise, the <select list> "*" is equivalent to a <value expression> sequence in which each <valueexpression> is a column reference that references a column of T and each column of T is referencedexactly once. The columns are referenced in the ascending sequence of their ordinal positionwithin T. > I don't think that relational model assigns any 'order' to columns. Correct, but SQL is not the relational model or vice versa. > BTW, SELECT * is just a different spelling of existing functionality ;) No, there is no other way to get a complete list of columns. (Hard-coding does not count.) -- Peter Eisentraut peter_e@gmx.net
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