Обсуждение: Inheritance and views

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Inheritance and views

От
DaVinci
Дата:
 Hello.

 I'd like to implement for my DB a mechanism of backup based in inherited
 tables. I explain it in detail:

 Idea is simple: table B inherits from table A. Anualy, data from table A is
 dumped in B. So, from frontend it is posible to access current data (from
 A) or all data (A + B).

 Problem is that I'd like also implement a view for A and B, but I don't
 know what is best way. View(s) must have rules for insert and update. Can
 view from A access data from B without problem (eliminating "ONLY" from
 select)?. Is there another better form of implementing this backup
 mechanism?. I'd not want to reinvent the wheel ;)

 Thanks for your ideas.

                                                 David

Re: Inheritance and views

От
"Eric G. Miller"
Дата:
On Wed, Apr 04, 2001 at 02:07:13PM +0200, DaVinci wrote:
>  Hello.
>
>  I'd like to implement for my DB a mechanism of backup based in inherited
>  tables. I explain it in detail:
>
>  Idea is simple: table B inherits from table A. Anualy, data from table A is
>  dumped in B. So, from frontend it is posible to access current data (from
>  A) or all data (A + B).
>
>  Problem is that I'd like also implement a view for A and B, but I don't
>  know what is best way. View(s) must have rules for insert and update. Can
>  view from A access data from B without problem (eliminating "ONLY" from
>  select)?. Is there another better form of implementing this backup
>  mechanism?. I'd not want to reinvent the wheel ;)
>
>  Thanks for your ideas.

Maybe...

SELECT * FROM A* ;

Notice the asterisk on the superclass table name.

--
Eric G. Miller <egm2@jps.net>