sqlite_to_mysql.rb

def interesting_tables
  ActiveRecord::Base.connection.tables
end

class BackupDB < ActiveRecord::Base
end

destination_db = 'new'
BackupDB.establish_connection destination_db.intern

interesting_tables.each do |tbl|
  unless tbl =~ /schema_mi/
    klass = tbl.classify.constantize

    BackupDB.connection.execute "DELETE FROM #{tbl} where id > 0"
    puts "Writing #{tbl}..."
    klass.find_in_batches do |data|
      data.each_with_index do |datum, i|
        puts "-- #{tbl} record #{i}"
        BackupDB.connection.execute "INSERT INTO #{tbl} (`#{datum.attributes.keys.join("`,`")}`) VALUES (#{datum.attributes.values.collect { |value| BackupDB.connection.quote(value) }.join(",")})"
      end
    end
  end
end