Don'tStopMusic

_ [Ruby] ActiveRecord1.6 と PostgreSQL 7.3

AciveRecord が使いたくなりました。仕事で Perl + PostgreSQL なウェブアプリに関わっているのですが、Ruby からも扱えるようにすると(専ら自分の)開発効率が上がるのになあ、というのが動機です。

が、これって PostgreSQL 7.3 系には対応してないんでしょうか。簡単な動作チェックのプログラムを書いたところ、information_schema がないよと怒られました。確か information_schema は PostgreSQL 7.4 で導入されたものなので、きっとそうなんだろうなあ。残念。

test.rb

#!/usr/bin/env ruby
require 'rubygems'
require_gem 'activerecord'
 
class User < ActiveRecord::Base
  def self.table_name
    "user"
  end
end
 
require 'logger'
ActiveRecord::Base.logger = Logger.new("debug.log")
ActiveRecord::Base.establish_connection(
  :adapter  => "postgresql",
  :host     => "assam",
  :username => "test",
  :password => "test",
  :database => "test"
)
 
user = User.find_all("name = 'foo'")[0]
puts user.name

実行結果

/usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/connection_adapters/abstract_adapter.rb:384:in `log': ERROR:  Namespace "information_schema" does not exist (ActiveRecord::StatementInvalid)
: SELECT column_name, column_default, character_maximum_length, data_type   FROM information_schema.columns  WHERE table_catalog = 'test'    AND table_schema = 'public'    AND table_name = 'test';        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/connection_adapters/postgresql_adapter.rb:155:in `table_structure'
        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/connection_adapters/postgresql_adapter.rb:52:in `columns'
        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/base.rb:538:in `columns'
        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/base.rb:543:in `columns_hash'
        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/base.rb:952:in `column_for_attribute'
        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/base.rb:1052:in `read_attribute'
        from /usr/local/ruby/lib/ruby/gems/1.8/gems/activerecord-1.6.0/lib/active_record/base.rb:1031:in `method_missing'
        from test.rb:22

追記

Active Record in Rails に

Database Support

My SQL, Postgre SQL (7.4+), and SQLite is supported out of the box. Writing a New database adapter is less than 100 lines of code.

とありました。うーむ。仕事で使ってる PostgreSQL を 7.4 に上げる画策をしますか……