Using Sequel to access postgres database in decoupled Rails app

Question

Can anyone tell me why I'm getting a "no database associated with Sequel::Model" error when trying to run specs in a decoupled rails app? My postgreSQL database has already been created and seeded using Rails (called "quizzy_development").

I have a "lib" directory outside of my rails ("web") app, which includes the following:

"environments.rb":

if ENV['APP_ENV'] == 'development'
  Quizzy.db = Quizzy::SQLDB.new
end

Sequel.connect(:adapter=>'postgres', :host=>'localhost', :database=>'quizzy_development')

"sql.rb":

require 'sequel'

module Quizzy
  class SQLDB
    class Question < Sequel::Model
    end

    def get_questions
    end

    def self.SQLDB
      @__orm_instance ||= SQLDB.new
    end
  end
end

"spec_helper.rb":

require 'pry-byebug'
require './quizzy'

"quizzy.rb":

module Quizzy
  def self.db=(database)
    @__db_instance = database
  end
end

require_relative "./db/sql.rb"
require_relative "./entities/question.rb"
require_relative "./entities/score.rb"
require_relative "./config/environments.rb"

"sql_spec.rb":

require 'spec_helper'

describe Quizzy::SQLDB do
  let(:db) { Quizzy::SQLDB.new }

  it "adds a question" do
  end

  it "gets all questions for a quiz" do
    questions = db.get_questions
  end

end

When I run the "Sequel.connect" code in irb it looks like it's working, but for some reason I'm unable to establish the connection when running through specs. Ideas?

Car · Accepted Answer · 2014-07-29 21:51:53Z

Here's the solution I found:

Sequel requires that you create a connection before running methods on it, but closes the database connection if it's not in use. Basically, the connection needs to be established whenever you want to call a method. This led to a bit of circular logic in that I was trying to call a method that would (I thought) establish a connection, but since the connection wasn't established I couldn't call the method.

So, one solution is to create a new file, "config.rb", in which the connection is established:

module Quizzy
  def self.SequelConnection
    @sequel_instance ||= Sequel.connect(:adapter=>'postgres', :host=>'localhost', :database=>'quizzy_development')
  end
  Quizzy.SequelConnection
end

The "sql.rb" file is then modified to require the config file and instantiate the connection:

require 'sequel'
require_relative "./config.rb"
module Quizzy
  class SQLDB
    def initialize
      @db = Quizzy.SequelConnection
    end

    class Question < Sequel::Model
    end

    def self.SQLDB
      @__orm_instance ||= SQLDB.new
    end
  end
end

I also removed the Sequel.connect line from "environments.rb".

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