column_for

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 654
        def column_for(table_name, column_name)
          unless column = columns(table_name).find { |c| c.name == column_name.to_s }
            raise "No such column: #{table_name}.#{column_name}"
          end
          column
        end