1 files changed, 19 insertions, 6 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
index 4fbc55a07e..72c6990ba5 100644
--- a/activerecord/lib/active_record/connection_adapters/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -13,11 +13,11 @@ module ActiveRecord
         ISO_DATETIME = /\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
       end
 
-      attr_reader :name, :default, :cast_type, :null, :sql_type, :default_function
+      attr_reader :name, :cast_type, :null, :sql_type, :default_function
 
       delegate :type, :precision, :scale, :limit, :klass, :accessor,
-        :text?, :number?, :binary?, :serialized?,
-        :type_cast, :type_cast_for_write, :raw_type_cast_for_write, :type_cast_for_database,
+        :text?, :number?, :binary?, :serialized?, :changed?,
+        :type_cast_from_user, :type_cast_from_database, :type_cast_for_database,
         :type_cast_for_schema,
         to: :cast_type
 
@@ -35,7 +35,7 @@ module ActiveRecord
         @cast_type        = cast_type
         @sql_type         = sql_type
         @null             = null
-        @default          = extract_default(default)
+        @original_default = default
         @default_function = nil
       end
 
@@ -51,8 +51,21 @@ module ActiveRecord
         Base.human_attribute_name(@name)
       end
 
-      def extract_default(default)
-        type_cast(default)
+      def default
+        @default ||= type_cast_from_database(@original_default)
+      end
+
+      def with_type(type)
+        dup.tap do |clone|
+          clone.instance_variable_set('@default', nil)
+          clone.instance_variable_set('@cast_type', type)
+        end
+      end
+    end
+
+    class NullColumn < Column
+      def initialize(name)
+        super name, nil, Type::Value.new
       end
     end
   end