ruby on rails - práctico - ¿Cómo usar ActiveRecord en un script de ruby fuera de Rails?

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Question

Tengo un pequeño script de ruby ​​en el que me gustaría usar ActiveRecord para acceder fácilmente a un modelo de base de datos. ¿Cuál es la mejor manera de hacerlo?

Answer 1

Puede crear un script mínimo con una base de datos SQLite en memoria en solo unas pocas líneas. Esta respuesta también está disponible como una Gist .

Inspirado en la publicación del blog de Jon Leighton sobre cómo publicar un impresionante informe de errores de ActiveRecord.

# Based on http://www.jonathanleighton.com/articles/2011/awesome-active-record-bug-reports/ 

# Run this script with `$ ruby my_script.rb`
require ''sqlite3''
require ''active_record''

# Use `binding.pry` anywhere in this script for easy debugging
require ''pry''

# Connect to an in-memory sqlite3 database
ActiveRecord::Base.establish_connection(
  adapter: ''sqlite3'',
  database: '':memory:''
)

# Define a minimal database schema
ActiveRecord::Schema.define do
  create_table :shows, force: true do |t|
    t.string :name
  end

  create_table :episodes, force: true do |t|
    t.string :name
    t.belongs_to :show, index: true
  end
end

# Define the models
class Show < ActiveRecord::Base
  has_many :episodes, inverse_of: :show
end

class Episode < ActiveRecord::Base
  belongs_to :show, inverse_of: :episodes, required: true
end

# Create a few records...
show = Show.create!(name: ''Big Bang Theory'')

first_episode = show.episodes.create!(name: ''Pilot'')
second_episode = show.episodes.create!(name: ''The Big Bran Hypothesis'')

episode_names = show.episodes.pluck(:name)

puts "#{show.name} has #{show.episodes.size} episodes named #{episode_names.join('', '')}."
# => Big Bang Theory has 2 episodes named Pilot, The Big Bran Hypothesis.

# Use `binding.pry` here to experiment with this setup.

Answer 2

Vale la pena señalar que en versiones posteriores de activerecord (v3 +) necesita requerirlo como tal

require "active_record"

Answer 3

require ''active_record''

# Change the following to reflect your database settings
ActiveRecord::Base.establish_connection(
  adapter:  ''mysql2'', # or ''postgresql'' or ''sqlite3'' or ''oracle_enhanced''
  host:     ''localhost'',
  database: ''your_database'',
  username: ''your_username'',
  password: ''your_password''
)

# Define your classes based on the database, as always
class SomeClass < ActiveRecord::Base
  #blah, blah, blah
end

# Now do stuff with it
puts SomeClass.find :all
some_class = SomeClass.new