From: Sean Chittenden <sean@...>
Date: 2002-02-06T02:49:15+09:00
Subject: Re: some dbi questions (probably postres specific)

> I'm playing around with dbi and postgres. After a while two problems
> remained that I couldn't solve so far.
> 
> 1. after doing a DBI::DatabaseHandle.select_all I get an array
> containing the result. In php I could also get the field names for
> the result. ( using pg_fieldname($result, $index)) Is there
> something similar in ruby's dbi?

Eh...  I'd avoid these, but that's just may reaction as a long time
DBI user.  The extra select to the system catalogs is a "bad thing" in
my opinion.

> 2. another problem arose when I tried wrapping objects around tables. I
>    created a table with the following structure:
>  Column|  Type   |                     Modifiers                        
> -------+---------+------------------------------------------------------
>  id    | integer | not null default nextval('"test_table_id_seq"'::text)
>  name  | text    | 
>  phone | text    | 
> 
>    now I insert some data into the table with the following code:
>    aConnection.execute "insert into test_table (name, phone) values
>                         ('foo', '42');"

id = dbh.select_one("SELECT currval('test_table_id_seq')")[0]

This is what all DBI's do under the hood.  After an insert into a
table with an incrementing sequence, the connection will honnor
curval(seq_name) which will return the value of the increment after
the insert into the row.  Just make sure that your user has read
access to the sequence.

-sc

-- 
Sean Chittenden