diff --git a/lib/rasti/db/collection.rb b/lib/rasti/db/collection.rb
index e2474ce..b0fcb76 100644
--- a/lib/rasti/db/collection.rb
+++ b/lib/rasti/db/collection.rb
@@ -16,6 +16,10 @@ def collection_name
           @collection_name ||= underscore(demodulize(name)).to_sym
         end
 
+        def collection_fields
+          @collection_fields ||= model.attributes - relations.keys
+        end
+
         def primary_key
           @primary_key ||= :id
         end
diff --git a/spec/collection_spec.rb b/spec/collection_spec.rb
index b320a9b..c3ba609 100644
--- a/spec/collection_spec.rb
+++ b/spec/collection_spec.rb
@@ -6,6 +6,7 @@
 
     it 'Implicit' do
       Users.collection_name.must_equal :users
+      Users.collection_fields.must_equal [:id, :name]
       Users.model.must_equal User
       Users.primary_key.must_equal :id
       Users.foreign_key.must_equal :user_id
@@ -13,6 +14,7 @@
 
     it 'Explicit' do
       People.collection_name.must_equal :people
+      People.collection_fields.must_equal [:document_number, :first_name, :last_name, :birth_date, :user_id]
       People.model.must_equal Person
       People.primary_key.must_equal :document_number
       People.foreign_key.must_equal :document_number