From: Pit Capitain <pit@...>
Date: 2005-11-28T17:52:09+09:00
Subject: Re: supporting/emulating updatable views in a ruby orm

Ara.T.Howard schrieb:
> 
> i've got a method to emulate updateable views in postgresql which is rather
> simple.  however, i'm wondering if any of the ruby orms out there would
> support such a beast.  for example, given:
> 
>     create table foo(
>       foo text,
>       id serial,
> 
>       primary key (id)
>     );
> 
>     create table bar(
>       bar text,
>       foo_id integer,
>       id serial,
> 
>       primary key (id),
>       foreign key (foo_id) references foo (id)
>     );
> 
>     create view foobar as
>       select
>         foo.foo as foo,
>         bar.bar as bar
>       from foo, bar
>       where foo.id = bar.foo_id;
> 
> i need to be able to do something like this:
> 
>   db = DB::new options
> 
>   foo = db.table "foo"
>   bar = db.table "bar"
> 
>   foobar = db.view "foobar"
> 
>   foobar[0]["foo"] = "42"
>   foobar[0]["bar"] = "forty-two"
> 
>   p foo[0]["foo"] #=> "42"
>   p bar[0]["bar"] #=> "forty-two"
> 
> i can do this using my code if the view is constructed a certain way, 
> but i'm
> wondering of any of the existing orms have addressed this rather common 
> need?

Ara, I don't have an answer for you, but some more questions. If I 
understand your code, you want to create new rows via the view foobar.

Do you want to create a new foo for every new bar? I don't think so, 
otherwise you could have both in the same table.

Do you want to allow two foos to have the same text? If not, you should 
add a unique key on the foo column to the foo table. Only then it should 
be possible to do what you want.

But as I said, I can't tell you anything about the Ruby ORM frameworks.

Regards,
Pit