diff --git a/lib/mongoid/fields.rb b/lib/mongoid/fields.rb
index 5a37bb2171..7a218255a8 100644
--- a/lib/mongoid/fields.rb
+++ b/lib/mongoid/fields.rb
@@ -413,7 +413,8 @@ def traverse_association_tree(key, fields, associations, aliased_associations)
       #
       # @api private
       def database_field_name(name, relations, aliased_fields, aliased_associations)
-        return nil unless name.present?
+        return "" unless name.present?
+
         key = name.to_s
         segment, remaining = key.split('.', 2)
 
diff --git a/lib/mongoid/touchable.rb b/lib/mongoid/touchable.rb
index ded0a8f884..c1c93f825c 100644
--- a/lib/mongoid/touchable.rb
+++ b/lib/mongoid/touchable.rb
@@ -78,7 +78,7 @@ def _gather_touch_updates(now, field = nil)
         field = database_field_name(field)
 
         write_attribute(:updated_at, now) if respond_to?("updated_at=")
-        write_attribute(field, now) if field
+        write_attribute(field, now) if field.present?
 
         touches = _extract_touches_from_atomic_sets(field) || {}
         touches.merge!(_parent._gather_touch_updates(now) || {}) if _touchable_parent?
diff --git a/spec/mongoid/attributes_spec.rb b/spec/mongoid/attributes_spec.rb
index f8f026d039..386b645f97 100644
--- a/spec/mongoid/attributes_spec.rb
+++ b/spec/mongoid/attributes_spec.rb
@@ -289,6 +289,22 @@
         end
       end
 
+      context "when given nil" do
+
+        it "returns nil" do
+         expect(person[nil]).to be nil
+        end
+
+      end
+
+      context "when given an empty string" do
+
+        it "returns nil" do
+         expect(person[""]).to be nil
+        end
+
+      end
+
       context "when the field was not explicitly defined" do
 
         context "when excluding with only and the field was not excluded" do
diff --git a/spec/mongoid/fields_spec.rb b/spec/mongoid/fields_spec.rb
index aed458fd61..9e7485b97c 100644
--- a/spec/mongoid/fields_spec.rb
+++ b/spec/mongoid/fields_spec.rb
@@ -1871,12 +1871,12 @@ class DiscriminatorChild2 < DiscriminatorParent
 
     context 'given nil' do
       subject { Person.database_field_name(nil) }
-      it { is_expected.to eq nil }
+      it { is_expected.to eq '' }
     end
 
     context 'given an empty String' do
       subject { Person.database_field_name('') }
-      it { is_expected.to eq nil }
+      it { is_expected.to eq '' }
     end
 
     context 'given a String' do