dump database to yaml for fixtures

gistfile1.rb

#
#= dump database to yaml for fixtures
#
# originated by elm200 <http://d.hatena.ne.jp/elm200/20070928/1190947947>
#
#== install
#
# move this file to RAILS_ROOT/lib/tasks/extract_fixtures.rake
#
namespace :db do
  fixtures_dir = "#{Rails.root}/tmp/fixtures/"
  namespace :fixtures do
    desc <<-DESC
      "Extract database data to the tmp/fixtures/ directory.
      Use FIXTURES=table_name[,table_name...] to specify table names to extract.
      Otherwise, all the table data will be extracted."
    DESC
    task :dump => :environment do
      def fixture_entry(table_name, obj)
        res = []
        klass = table_name.singularize.camelize.constantize
        res << "#{table_name.singularize}#{obj['id']}:"
        klass.columns.each do |column|
          x = obj[column.name]
          if column.text? then x = "\"#{x}\"" end
          res << " #{column.name}: #{x}"
        end
        res.join("\n")
      end
    
      sql = "SELECT * FROM %s ORDER BY id"
      skip_tables = ["schema_migrations"]
      ActiveRecord::Base.establish_connection
      sh "mkdir -p #{fixtures_dir}"

      if ENV['FIXTURES']
        table_names = ENV['FIXTURES'].split(/,/)
      else
        table_names = (ActiveRecord::Base.connection.tables - skip_tables)
      end

      table_names.each do |table_name|
        File.open("#{fixtures_dir}#{table_name}.yml", "w") do |file|
          objects  = ActiveRecord::Base.connection.select_all(sql % table_name)
          objects.each do |obj|
            file.write  fixture_entry(table_name, obj) + "\n\n"
          end
        end
      end
    end
  end
end