From: Kendall Gifford <zettabyte@...>
Date: 2012-03-23T07:54:05+09:00
Subject: Re: ActiveRecord and working with sequences

On Thu, Mar 22, 2012 at 12:22 PM, David Kerr <dmk@mr-paradox.net> wrote:
> Howdy,
>
> (sorry if this ends up as a duplicate post, my subscription was messed up)
>
> I'm very new with ruby and ActiveRecord.

The first thing you should know is that there is a Ruby on Rails
specific group where rails-specific questions should go:

https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-talk

>
> I've got a table in postgres that looks something like
>
> create table test
>   test_id       not null default nextval('test_id_seq')
>   test_parent   int not null
>   test_name     varchar(20) not null
>
>
> For the parent record, test_parent = test_id.
> I can't change the schema, so i need to work with the table structure I
> have.
>
>
> What's the best way to handle that situation in ActiveRecord?
>
> It seems like i should do something like:
> SEQ = <code to select nextval('test_id_seq')>
> Test.new(:test_id => SEQ, :test_parent => SEQ, :test_name => 'woohoo' );
>
>
> I'm not sure how to active the <code to select nextval()> portion with
> ActiveRecord.
>
> I tried:
> seq = ActiveRecord::Base.connection.execute("SELECTnextval('test_id_seq')")
>
> And that seems to be doable, but the PG:Result class is a little weird, so I
> was hoping there was a better way.
>
>
> Thanks.
>
> Dave
>

As for using PostgreSQL sequences, check out:

http://api.rubyonrails.org/classes/ActiveRecord/ModelSchema/ClassMethods.html#method-i-sequence_name-3D


-- 
Kendall Gifford
zettabyte@gmail.com