diff --git a/lib/jsonapi/deserializable/relationship.rb b/lib/jsonapi/deserializable/relationship.rb
index deb87fd..56e809e 100644
--- a/lib/jsonapi/deserializable/relationship.rb
+++ b/lib/jsonapi/deserializable/relationship.rb
@@ -24,23 +24,25 @@ module JSONAPI
         deserialize!
       end
 
-      def to_h
+      def to_hash
         @hash
       end
+      alias to_h to_hash
 
       private
 
       def deserialize!
         @hash = {}
+        return unless @document.key?('data')
         if @data.is_a?(Array)
           deserialize_has_many!
-        else
+        elsif @data.nil? || @data.is_a?(Hash)
           deserialize_has_one!
         end
       end
 
       def deserialize_has_one!
-        return unless self.class.has_one_block && @document.key?('data')
+        return unless self.class.has_one_block
         id = @data && @data['id']
         type = @data && @data['type']
         instance_exec(@document, id, type, &self.class.has_one_block)
diff --git a/lib/jsonapi/deserializable/resource.rb b/lib/jsonapi/deserializable/resource.rb
index 7729cbd..e08944a 100644
--- a/lib/jsonapi/deserializable/resource.rb
+++ b/lib/jsonapi/deserializable/resource.rb
@@ -6,13 +6,12 @@ module JSONAPI
       include ResourceDSL
 
       class << self
-        attr_accessor :type_block, :id_block
-        attr_accessor :attr_blocks
-        attr_accessor :has_one_rel_blocks, :has_many_rel_blocks
+        attr_accessor :type_block, :id_block, :attr_blocks,
+                      :has_one_rel_blocks, :has_many_rel_blocks
       end
 
       self.attr_blocks = {}
-      self.has_one_rel_blocks = {}
+      self.has_one_rel_blocks  = {}
       self.has_many_rel_blocks = {}
 
       def self.inherited(klass)
@@ -38,9 +37,10 @@ module JSONAPI
         deserialize!
       end
 
-      def to_h
+      def to_hash
         @hash
       end
+      alias to_h to_hash
 
       private