OG: Redo your migrations in Rails and keep your data over 8 years ago Quite often early in a project I find myself editing migration scripts, and wanting to keep my development data. https://samsaffron.com/archive/2008/02/02/Redo+your+migrations+in+Rails+and+keep+your+data

db_redo.rake

def interesting_tables
  rval = ActiveRecord::Base.connection.tables.sort
  rval.reject! do |tbl|
    ['schema_migrations','schema_info', 'sessions', 'public_exceptions'].include?(tbl)
  end
  rval
end

namespace :db do
  namespace :backup do
    
      
    desc "Reload the database and rerun migrations"
    task :redo do 
      Rake::Task['db:backup:write'].invoke
      Rake::Task['db:drop'].invoke
      Rake::Task['db:create'].invoke
      Rake::Task['db:migrate'].invoke
      Rake::Task['db:backup:read'].invoke 
    end 
  
    desc "Dump entire db."
    task :write => :environment do 

      dir = RAILS_ROOT + '/db/backup'
      FileUtils.mkdir_p(dir)
      FileUtils.chdir(dir)
      interesting_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
      FileUtils.chdir(RAILS_ROOT)
    end
    
    desc "Loads the entire db."
    task :read => [:environment, 'db:schema:load'] do 

      dir = RAILS_ROOT + '/db/backup'
      FileUtils.mkdir_p(dir)
      FileUtils.chdir(dir)
    
      interesting_tables.each do |tbl|

        ActiveRecord::Base.transaction do 

          begin 
            klass = tbl.classify.constantize
            klass.destroy_all
            klass.reset_column_information
          
            puts "Loading #{tbl}..."
            YAML.load_file("#{tbl}.yml").each do |fixture|
              data = {}
              klass.columns.each do |c|
                # filter out missing columns 
                data[c.name] = fixture[c.name] if fixture[c.name]
              end         
              ActiveRecord::Base.connection.execute "INSERT INTO #{tbl} (#{data.keys.map{|kk| "#{tbl}.#{kk}"}.join(",")}) VALUES (#{data.values.collect { |value| ActiveRecord::Base.connection.quote(value) }.join(",")})", 'Fixture Insert'
            
            end        
          rescue 
            puts "failed to load table #{tbl}" 
          end 
        end
      end
    
    end
  
  end
end