Come utilizzare ActiveRecord in uno script rubino all'esterno di Rails?

Question

Ho un piccolo script rubino in cui mi piacerebbe utilizzare ActiveRecord per accedere facilmente a un modello di database. Qual'è il miglior modo di farlo?

Answer 1

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 

Answer 2

Vale la pena notare che nelle versioni successive di ActiveRecord (v3 +) è necessario richiedere in questa maniera

require "active_record" 

Answer 3

È possibile creare uno script minimo con un database SQLite in memoria in pochi Linee. Questa risposta è anche available as a Gist.

Ispirato da Jon Leighton's blog post su come pubblicare un rapporto sui bug di 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.