Easy migration between databases

backup.rake

#
# Original blog here http://bit.ly/5AutLA
#

namespace :db do
  namespace :backup do
    
    def tables
      ActiveRecord::Base.connection.tables.sort.reject do |tbl|
        ['schema_migrations'].include?(tbl)
      end
    end
  
    desc "Dump entire db."
    task :write => :environment do
      dir = RAILS_ROOT + '/db/backup'
      FileUtils.mkdir_p(dir)
      FileUtils.chdir(dir)
    
      tables.each do |tbl|
        klass = tbl.classify.constantize
        puts "Writing #{tbl}..."
        File.open("#{tbl}.yml", 'w+') { |f| YAML.dump klass.find(:all).collect(&:attributes), f }      
      end    
    end
  
    desc "Load YML files from /db/backup/ into the database"
    task :read => :environment do
      dir = RAILS_ROOT + '/db/backup'
      FileUtils.mkdir_p(dir)
      FileUtils.chdir(dir)
    
      tables.each do |tbl|
        klass = tbl.classify.constantize
        
        ActiveRecord::Base.transaction do
          if File::exists?("#{tbl}.yml")
            puts "Loading #{tbl}..."
            YAML.load_file("#{tbl}.yml").each do |fixture|            
              ActiveRecord::Base.connection.execute "INSERT INTO #{tbl} (#{fixture.keys.join(",")}) VALUES (#{fixture.values.collect { |value| ActiveRecord::Base.connection.quote(value) }.join(",")})", 'Fixture Insert'
            end
          end
        end
      end    
    end
  
  end
end

Originally taken from http://bit.ly/5AutLA