session topological sorted table creation (progress)

source/core/object/relation_endpoint.cpp

@@ -25,6 +25,10 @@ const schema_node &relation_endpoint::node() const {
   return *node_;
 }
 
+std::shared_ptr<schema_node> relation_endpoint::node_ptr() const {
+  return node_;
+}
+
 bool relation_endpoint::is_has_one() const {
   return type_ == relation_type::HAS_ONE;
 }