Best way to export a database table to a YAML file?

Question

I have some data in my development database that I would like to utilize as fixtures in my test environment. What is the best way in Rails 2.x to export a database table to

Answer 1

rake db:fixtures:dump

has been changed to

rake db:extract_fixtures

Answer 2

I have been using YamlDb to save the state of my database.

Install it with the following command:

script/plugin install git://github.com/adamwiggins/yaml_db.git 

Use the rake task to dump the contents of Rails database to db/data.yml

rake db:data:dump

Use the rake task to load the contents of db/data.yml into the database

rake db:data:load

This is the creators homepage:

http://blog.heroku.com/archives/2007/11/23/yamldb_for_databaseindependent_data_dumps/

Answer 3

Here's a rake task that will do exactly that (tested in Rails 3.2.8):

namespace :db do
    task :extract_fixtures => :environment do
      sql  = 'SELECT * FROM "%s"'
      skip_tables = ["schema_migrations"]
      ActiveRecord::Base.establish_connection
      if (not ENV['TABLES'])
        tables = ActiveRecord::Base.connection.tables - skip_tables
      else
        tables = ENV['TABLES'].split(/, */)
      end
      if (not ENV['OUTPUT_DIR'])
        output_dir="#{Rails.root}/test/fixtures"
      else
        output_dir = ENV['OUTPUT_DIR'].sub(/\/$/, '')
      end
      (tables).each do |table_name|
        i = "000"
        File.open("#{output_dir}/#{table_name}.yml", 'w') do |file|
          data = ActiveRecord::Base.connection.select_all(sql % table_name.upcase)
          file.write data.inject({}) { |hash, record|
            hash["#{table_name}_#{i.succ!}"] = record
            hash
          }.to_yaml
          puts "wrote #{table_name} to #{output_dir}/"
        end
      end
    end
end

Source: http://sachachua.com/blog/2011/05/rails-exporting-data-specific-tables-fixtures/

Note: I had to make a few changes to the blog code to make it more cross-database compatible and work in Rails 3.2

Answer 4

 > rails c
 irb> puts Modelname.all.to_yaml

then copy & paste it in file and edit it to match what fixtures expect.

It's manual labor but if you need this just once probably the fastest way.

Answer 5

For Rails 3, if you want to dump yaml from the DB and use it as a fixture, I use this code:

module DbToFixture

  TEMP_FIXTURE_PATH = Rails.root.join("test", "new_fixtures")

  def fixturize(model)
    Dir.mkdir(TEMP_FIXTURE_PATH) unless File.exists?(TEMP_FIXTURE_PATH)
    fname = model.table_name
    file_path = TEMP_FIXTURE_PATH.join(fname)
    File.open(file_path, 'w') do |f|
      model.all.each do |m|
        f.write(m.to_yaml)
      end
    end
  end

end

I just run it from the console with

require './lib/db_to_fixture'
include DbToFixture
fixturize ModelName

I have not been able to get ar_fixtures to work with Rails 3 (haven't tried very hard though). Yaml db is great for dumping and saving the db, but its format is not compatible with fixtures.

Answer 6

For dumping for rspec/cucumber test fixtures in Rails 3 this is the best answer I've found: What is the standard way to dump db to yml fixtures in rails?