diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 78b3507..0eb5bd3 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1734,19 +1734,22 @@ MSG
         callstack.each do |name, values_with_empty_parameters|
           begin
             klass = (self.class.reflect_on_aggregation(name.to_sym) || column_for_attribute(name)).klass
-            # in order to allow a date to be set without a year, we must keep the empty values.
-            # Otherwise, we wouldn't be able to distinguish it from a date with an empty day.
-            values = values_with_empty_parameters.reject { |v| v.nil? }
+            values = values_with_empty_parameters.map { |v| v.last }
 
-            if values.empty?
+            unless values.any? { |v| !v.nil? }
               send(name + "=", nil)
             else
 
               value = if Time == klass
-                instantiate_time_object(name, values)
+                if values_with_empty_parameters.map(&:first) & [1, 2, 3] != [1, 2, 3]
+                  errors << AttributeAssignmentError.new("error on assignment #{values.inspect} to #{name}", nil, name)
+                else
+                  (0..2).each { |i| values[i] = 1 if values[i].nil? }
+                  instantiate_time_object(name, values)
+                end
               elsif Date == klass
                 begin
-                  values = values_with_empty_parameters.collect do |v| v.nil? ? 1 : v end
+                  values = values.collect do |v| v.nil? ? 1 : v end
                   Date.new(*values)
                 rescue ArgumentError => ex # if Date.new raises an exception on an invalid date
                   instantiate_time_object(name, values).to_date # we instantiate Time object and convert it back to a date thus using Time's logic in handling invalid dates
@@ -1778,7 +1781,7 @@ MSG
           attributes[attribute_name] << [ find_parameter_position(multiparameter_name), parameter_value ]
         end
 
-        attributes.each { |name, values| attributes[name] = values.sort_by{ |v| v.first }.collect { |v| v.last } }
+        attributes.each { |name, values| attributes[name] = values.sort_by{ |v| v.first } }
       end
 
       def type_cast_attribute_value(multiparameter_name, value)
@@ -1786,7 +1789,7 @@ MSG
       end
 
       def find_parameter_position(multiparameter_name)
-        multiparameter_name.scan(/\(([0-9]*).*\)/).first.first
+        multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i
       end
 
       # Returns a comma-separated pair list, like "key1 = val1, key2 = val2".
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 16fd9a7..156c30d 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -598,6 +598,46 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
   end
 
+  def test_multiparameter_attributes_on_time_will_raise_on_big_time_if_missing_parts
+    attributes = {
+      "written_on(4i)" => "16", "written_on(5i)" => "24"
+    }
+    topic = Topic.find(1)
+    assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      topic.attributes = attributes
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_raise_on_small_time_if_missing_parts
+    attributes = {
+      "written_on(4i)" => "16", "written_on(5i)" => "12", "written_on(6i)" => "02"
+    }
+    topic = Topic.find(1)
+    assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      topic.attributes = attributes
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_date_if_empty
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "16", "written_on(5i)" => "24"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_equal Time.local(1, 1, 1, 16, 24), topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_with_seconds_will_ignore_date_if_empty
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "16", "written_on(5i)" => "12", "written_on(6i)" => "02"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_equal Time.local(1, 1, 1, 16, 12, 02), topic.written_on
+  end
+
   def test_multiparameter_assignment_of_aggregation
     customer = Customer.new
     address = Address.new("The Street", "The City", "The Country")