Re: [HACKERS] Postgresql OO Patch
От | Robert B. Easter |
---|---|
Тема | Re: [HACKERS] Postgresql OO Patch |
Дата | |
Msg-id | 00052203484408.14806@comptechnews обсуждение исходный текст |
Ответ на | Re: [HACKERS] Postgresql OO Patch (Peter Eisentraut <peter_e@gmx.net>) |
Ответы |
Re: Re: [HACKERS] Postgresql OO Patch
|
Список | pgsql-general |
On Sun, 21 May 2000, Chris Bitmead wrote: > Peter Eisentraut wrote: > > > > Chris writes: > > > > > I.e. "SELECT * FROM foobar*" becomes "SELECT * FROM foobar", and > > > "SELECT * from foobar" becomes "SELECT * FROM ONLY foobar". > > > > This aspect of the patch I wholeheartedly agree on. The rest I'm not sure > > about -- yet. :) > > > > > Benefits: > > > *) SQL3 says it. > > I also agree about the usage of ONLY, as long as it follows the official standardized SQL3 spec. About returning multiple types of rows again: I don't see that in SQL3 so far (difficult and time consuming to read). If it were allowed, you might have to specify the level to dig to in the tree. The rows are shared among supertable and subtables. One row in a leaf table has subrows in all its supertables up the tree. If you do a "SELECT * FROM supertable*" (for example, if you were to redefine table* to mean select heterogeneous rows), what row will you get for a row that exists in a leaf? The same row is in all tables between supertable and the leaf. I suppose it would be necessary to have the query check each row and see how far down the tree it goes, or the system keeps track of that and returns the row-type from the table that inserted it. OR, there could be some extra specifier like "SELECT * FROM supertable DIGGING TO LEVEL 3". In this case, it would only look down into the tree to 3 levels below supertable and you'd never get row-types that are down lower than level 3. Anyhow, I still don't think returning multple row-types is going to happen, not that I have any authority one way or the other! :-) -- Robert B. Easter reaster@comptechnews.com
В списке pgsql-general по дате отправления: