Re: [HACKERS] Inheritance, referential integrity and other constraints
От | Peter Eisentraut |
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Тема | Re: [HACKERS] Inheritance, referential integrity and other constraints |
Дата | |
Msg-id | Pine.LNX.4.21.0001271958490.356-100000@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: [HACKERS] Inheritance, referential integrity and other constraints ("Oliver Elphick" <olly@lfix.co.uk>) |
Список | pgsql-hackers |
On 2000-01-26, Oliver Elphick mentioned: > >considered right. Also I just looked into item 'Disallow inherited columns > >with the same name as new columns' and it seems that someone actually made > >provisions for this to be allowed, meaning that > >create table test1 (x int); > >create table test2 (x int) inherits (test1); > >would result in test2 looking exactly like test1. No one knows what the > >motivation was. (I removed it anyway.) > > That's a relief! Unless you have actually removed the ability to do > repeated inheritance? Ugh, I just realized that of course you _have_ to allow duplicate column names, e.g. in a scheme like b a < > d c the columns of "a" would arrive duplicated at "d" and the above logic would merge them. I haven't finished that fix yet, so I better scrap it now. Seem like this TODO item was really a non-starter. > Final note: I have just realised that most of what I am using inheritance > for could be done with views and unions, provided that we can REFERENCE a > view (which I haven't tested). One really radical option would be to strip > out inheritance altogether! Sure, I could live with that. It's not like it ever worked (in its entirety). And any table a (a1, a2, a3) table b (b1, b2) inherits (a) can also be implemented as table a (a_id, a1, a2, a3) table b_bare (b_id, b1, b2) create view b as select a1, a2, a3, b1, b2 from outer join a, b on a_id = b_id {or whatever that syntax was} plus an insert rule or two. It would make the rest of the code soooo much easier. (Sarcasm intended, but a glimpse of truth as well.) +++ Slashdot: "Self-proclaimed most advanced open-source database drops object-oriented facilities to simplify code base" AC reply: "Now when's KDE moving to C?" +++ -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden
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