diff --git a/lib/couchrest/model/base.rb b/lib/couchrest/model/base.rb
index b22e8d3..5a80d49 100644
--- a/lib/couchrest/model/base.rb
+++ b/lib/couchrest/model/base.rb
@@ -98,11 +98,14 @@ module CouchRest
       def persisted?
         !new?
       end
+      
+      def to_key
+        new? ? nil : [id] 
+      end
 
+      alias :to_param :id
       alias :new_record? :new?
       alias :new_document? :new?
-      alias :to_key :id
-      alias :to_param :id
     end    
   end
 end
diff --git a/spec/couchrest/base_spec.rb b/spec/couchrest/base_spec.rb
index a79110a..70057a4 100644
--- a/spec/couchrest/base_spec.rb
+++ b/spec/couchrest/base_spec.rb
@@ -40,7 +40,7 @@ describe "Model Base" do
     end
   end
  
-  describe "ActiveModel compatability" do
+  describe "ActiveModel compatability Basic" do
 
     before(:each) do 
       @obj = Basic.new(nil)
@@ -54,9 +54,9 @@ describe "Model Base" do
       end
 
       context "when the document is not new" do
-        it "returns id" do
+        it "returns id in an array" do
           @obj.save
-          @obj.to_key.should eql(@obj['_id'])
+          @obj.to_key.should eql([@obj['_id']])
         end
       end
     end
@@ -91,6 +91,13 @@ describe "Model Base" do
       end
     end
 
+    describe "#model_name" do
+      it "returns the name of the model" do
+        @obj.class.model_name.should eql('Basic')
+        WithDefaultValues.model_name.human.should eql("With default values")
+      end
+    end
+
 
   end