diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 07c88594969a02c4773ea762ad8d438a7027b6ec..90701938e5fe814a23bba878782e8a3aa6d26d76 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -32,36 +32,21 @@ def cache_attribute?(attr_name)
 
         protected
 
-        # We want to generate the methods via module_eval rather than
-        # define_method, because define_method is slower on dispatch and
-        # uses more memory (because it creates a closure).
+        # We want to generate the methods via module_eval rather than define_method,
+        # because define_method is slower on dispatch and uses more memory (because it
+        # creates a closure).
         #
-        # But sometimes the database might return columns with
-        # characters that are not allowed in normal method names (like
-        # 'my_column(omg)'. So to work around this we first define with
-        # the __temp__ identifier, and then use alias method to rename
-        # it to what we want.
-        #
-        # We are also defining a constant to hold the frozen string of
-        # the attribute name. Using a constant means that we do not have
-        # to allocate an object on each call to the attribute method.
-        # Making it frozen means that it doesn't get duped when used to
-        # key the @attributes_cache in read_attribute.
-        def define_method_attribute(name)
-          safe_name = name.unpack('h*').first
+        # But sometimes the database might return columns with characters that are not
+        # allowed in normal method names (like 'my_column(omg)'. So to work around this
+        # we first define with the __temp__ identifier, and then use alias method to
+        # rename it to what we want.
+        def define_method_attribute(attr_name)
           generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
-            module AttrNames
-              unless defined? ATTR_#{safe_name}
-                ATTR_#{safe_name} = #{name.inspect}.freeze
-              end
+            def __temp__
+              read_attribute('#{attr_name}') { |n| missing_attribute(n, caller) }
             end
-
-            def __temp__#{safe_name}
-              read_attribute(AttrNames::ATTR_#{safe_name}) { |n| missing_attribute(n, caller) }
-            end
-
-            alias_method #{name.inspect}, :__temp__#{safe_name}
-            undef_method :__temp__#{safe_name}
+            alias_method '#{attr_name}', :__temp__
+            undef_method :__temp__
           STR
         end
 
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index cd33494cc3453706a325b8b62ebd81eda0ddd731..fa9097db1fea5a573ea5d8f06ba3ae783a5b9cb7 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -9,19 +9,15 @@ module Write
 
       module ClassMethods
         protected
-
-        # See define_method_attribute in read.rb for an explanation of
-        # this code.
-        def define_method_attribute=(name)
-          safe_name = name.unpack('h*').first
-          generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
-            def __temp__#{safe_name}=(value)
-              write_attribute(AttrNames::ATTR_#{safe_name}, value)
+          def define_method_attribute=(attr_name)
+            if attr_name =~ ActiveModel::AttributeMethods::NAME_COMPILABLE_REGEXP
+              generated_attribute_methods.module_eval("def #{attr_name}=(new_value); write_attribute('#{attr_name}', new_value); end", __FILE__, __LINE__)
+            else
+              generated_attribute_methods.send(:define_method, "#{attr_name}=") do |new_value|
+                write_attribute(attr_name, new_value)
+              end
             end
-            alias_method #{(name + '=').inspect}, :__temp__#{safe_name}=
-            undef_method :__temp__#{safe_name}=
-          STR
-        end
+          end
       end
 
       # Updates the attribute identified by <tt>attr_name</tt> with the