Added new #update_column method.

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index 3c4dab304e..7661676f8c 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -32,6 +32,7 @@ module ActiveRecord
           @attributes[attr_name] = value
         end
       end
+      alias_method :raw_write_attribute, :write_attribute
 
       private
         # Handle *= for method_missing.
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 17a64b6e86..a916c88348 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -119,6 +119,20 @@ module ActiveRecord
       save(:validate => false)
     end
 
+    # Updates a single attribute of an object, without calling save.
+    #
+    # * Validation is skipped.
+    # * Callbacks are skipped.
+    # * updated_at/updated_on column is not updated if that column is available.
+    #
+    def update_column(name, value)
+      name = name.to_s
+      raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name)
+      raise ActiveRecordError, "can not update on a new record object" unless persisted?
+      raw_write_attribute(name, value)
+      self.class.update_all({ name => value }, self.class.primary_key => id) == 1
+    end
+
     # Updates the attributes of the model from the passed-in hash and saves the
     # record, all wrapped in a transaction. If the object is invalid, the saving
     # will fail and false will be returned.