diff --git a/lib/dm-core/associations/relationship.rb b/lib/dm-core/associations/relationship.rb
index 7b28d9b..cc496d7 100644
--- a/lib/dm-core/associations/relationship.rb
+++ b/lib/dm-core/associations/relationship.rb
@@ -12,7 +12,7 @@ module DataMapper
           child_key = parent_key.zip(@child_properties || []).map do |parent_property,property_name|
             # TODO: use something similar to DM::NamingConventions to determine the property name
             property_name ||= "#{name}_#{parent_property.name}".to_sym
-            model_properties[property_name] || DataMapper.repository(repository_name) { child_model.property(property_name, parent_property.type) }
+            model_properties[property_name] || DataMapper.repository(repository_name) { child_model.property(property_name, parent_property.type, :length => parent_property.length) }
           end
 
           PropertySet.new(child_key)