Thanks to all...
another question...
is it possible to copy a table to a view and then back the view to a
table???
thank you very much...
ivan
Il giorno ven, 03/03/2006 alle 11.51 +0100, Andreas Kretschmer ha
scritto:
> ivan marchesini <marchesini@unipg.it> schrieb:
>
> > Dear users..
> > I have fastly created a table in a postgresql database..
> > some columns where edited by hand (columns A, B, C), and some others
> > (columns D, E, F) have been calculated as a result of mathematical
> > equation (where the factors are the A, B, C columns)....
>
> You should create a table with (a,b,c) and a view. Below a example.
>
> test=# create table foo (a int, b int, c int);
> CREATE TABLE
>
> test=# create view foo_view as (select a,b,c,a*b as ab, a*c as ac, b*c as bc from foo);
> CREATE VIEW
>
>
> > now I simply need to change some values in the A, B, C columns and I
> > would like to obtain the correct values in the D, E, F column...
> > I know that this is a tipical problem of a spreadsheet but how can I
> > solve it with a DBMS??
>
> test=# insert into foo values (2,3,4);
> INSERT 0 1
> test=# select * from foo_view ;
> a | b | c | ab | ac | bc
> ---+---+---+----+----+----
> 2 | 3 | 4 | 6 | 8 | 12
> (1 row)
>
> test=# update foo set a=3;
> UPDATE 1
> test=# select * from foo_view ;
> a | b | c | ab | ac | bc
> ---+---+---+----+----+----
> 3 | 3 | 4 | 9 | 12 | 12
> (1 row)
>
>
> HTH, Andreas
--
Ivan Marchesini
Department of Civil and Environmental Engineering
University of Perugia
Via G. Duranti 93/a
06125
Perugia (Italy)
e-mail: marchesini@unipg.it ivan.marchesini@gmail.com
tel: +39(0)755853760
fax: +39(0)755853756