Обсуждение: Tutorial : using foreign keys, retrictions etc

Hi,
       I've decided to switch from mysql to postgresql as my database server. I 
do mostly web programming (who doesnt these days?) with more than a 100 
sites developed (using mysql).
       I've read about postgresql and it's features (such as triggers, stored 
procedures, views) and I'd like to know if there is some tutorial/snippet 
of code regarding such features specially  the use of foreign keys and 
referetial integrity.
       To give a more concrete example the next app I'd like to use postgresql 
needs this behaviour :

table A
id,  name

table B
id, foo

table C
id, date
       If I change id in table A update table B to change it too (I think it's 
called cascade).
       Thanks.

- RM       

On Sat, 2 Jun 2001, Mario Bittencourt wrote:

> Hi,
> 
>         I've decided to switch from mysql to postgresql as my database server. I 
> do mostly web programming (who doesnt these days?) with more than a 100 
> sites developed (using mysql).
> 
>         I've read about postgresql and it's features (such as triggers, stored 
> procedures, views) and I'd like to know if there is some tutorial/snippet 
> of code regarding such features specially  the use of foreign keys and 
> referetial integrity.
> 
>         To give a more concrete example the next app I'd like to use postgresql 
> needs this behaviour :
> 
> table A
> id,  name
> 
> table B
> id, foo
> 
> table C
> id, date
> 
>         If I change id in table A update table B to change it too (I think it's 
> called cascade).

In this case it's pretty easy, 
table B needs a foreign key defined like:FOREIGN KEY (id) REFERENCES A(id) ON UPDATE CASCADE
(you may want ON DELETE CASCADE as well, it depends).

I believe someone had written a document on FK, but I'm not entirely sure
what happened to it or whether it ended up in the docs.  For examples
without much explanation you can look at the foreign key regression test,
but that's not alot of help.

On Sat, Jun 02, 2001 at 06:49:55PM -0400, Mario Bittencourt wrote:
> Hi,
> 
>         I've decided to switch from mysql to postgresql as my database server.
Good for you :)

> procedures, views) and I'd like to know if there is some tutorial/snippet 
> of code regarding such features specially  the use of foreign keys and 
> referetial integrity.
You might want to look at http://techdocs.postgresql.org. IIRC, a script to "port" MySQL code to PostgreSQL has been
includedin
 
the contrib section of 7.1.x.For examples of functions, head to http://www.brasileiro.net/postgres
-Roberto
-- 
+----| http://fslc.usu.edu USU Free Software & GNU/Linux Club |------+ Roberto Mello - Computer Science, USU -
http://www.brasileiro.net      http://www.sdl.usu.edu - Space Dynamics Lab, Developer    
 
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