From 0d93b9b1edafebabc1e315e3c96705300f268054 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sascha=20K=C3=BChl?= <s.kuehl@tms-bonn.de>
Date: Mon, 14 Jul 2025 15:57:14 +0200
Subject: [PATCH] attaching schema nodes progress

---
 demo/work.cpp                                 | 17 +++++--
 .../matador/object/attribute_definition.hpp   |  5 +-
 .../object/attribute_definition_generator.hpp | 39 +++++++++++-----
 include/matador/object/basic_object_info.hpp  |  5 +-
 include/matador/object/object_info.hpp        | 12 ++---
 include/matador/object/relation_completer.hpp | 26 +++++------
 include/matador/object/schema.hpp             | 11 +++--
 include/matador/object/schema_node.hpp        | 31 +++++++++----
 .../matador/object/schema_node_iterator.hpp   | 12 ++---
 include/matador/utils/error.hpp               |  2 +-
 source/core/object/attribute_definition.cpp   |  8 ++++
 .../object/attribute_definition_generator.cpp |  8 +++-
 source/core/object/basic_object_info.cpp      | 13 ++----
 source/core/object/schema.cpp                 |  6 +--
 source/core/object/schema_node.cpp            | 46 ++++++++++++++++---
 source/core/object/schema_node_iterator.cpp   | 10 ++--
 source/core/utils/error.cpp                   | 11 +++--
 source/orm/orm/session.cpp                    |  9 +++-
 source/orm/query/query_compiler.cpp           |  2 +-
 19 files changed, 182 insertions(+), 91 deletions(-)

diff --git a/demo/work.cpp b/demo/work.cpp
index d6283d9..1c939dd 100644
--- a/demo/work.cpp
+++ b/demo/work.cpp
@@ -70,9 +70,13 @@ using namespace work::models;
 // payload.is_polymorphic_type<jobs::IdPayload>();
 
 int main() {
+    logger::default_min_log_level(logger::log_level::LVL_DEBUG);
+    logger::add_log_sink(logger::create_stdout_sink());
+
     const object::schema schema("Administration");
 
-    sql::connection_pool<sql::connection> pool("postgres://test:test123!@127.0.0.1:5432/matador", 4);
+    sql::connection_pool<sql::connection> pool("postgres://news:news@127.0.0.1:15432/matador", 4);
+    // sql::connection_pool<sql::connection> pool("postgres://test:test123!@127.0.0.1:5432/matador", 4);
 
     orm::session ses(pool);
 
@@ -92,14 +96,20 @@ int main() {
         .and_then([&ses] { return ses.attach<jobs::IdPayload, jobs::Payload>("id_list_payloads"); })
         .and_then([&ses] { return ses.attach<jobs::IdListPayload, jobs::Payload>("id_payloads"); })
         .and_then([&ses] { return ses.attach<jobs::Task>("tasks"); })
-        .and_then([&ses] { return ses.create_schema(); });
+    ;
+    // ses.dump_schema(std::cout);
 
     if (!result) {
         std::cout << "error: " << result.err().message() << std::endl;
         return 0;
     }
 
-    ses.dump_schema(std::cout);
+    result = ses.create_schema();
+    if (!result) {
+        std::cout << "error: " << result.err() << std::endl;
+        return 0;
+    }
+
     // const std::string dns{"sqlite://demo.db"};
     // sql::connection c(dns);
     //
@@ -110,7 +120,6 @@ int main() {
     //     return 0;
     // }
 
-
     return 0;
 }
 
diff --git a/include/matador/object/attribute_definition.hpp b/include/matador/object/attribute_definition.hpp
index 75413f7..c32b31d 100644
--- a/include/matador/object/attribute_definition.hpp
+++ b/include/matador/object/attribute_definition.hpp
@@ -25,6 +25,7 @@ public:
   attribute_definition(attribute_definition&&) noexcept = default;
   attribute_definition& operator=(attribute_definition&&) noexcept = default;
 
+  attribute_definition() = default;
   template<typename Type>
   explicit attribute_definition(std::string name, std::string table_name, const utils::field_attributes& attr)
   : attribute_definition(std::move(name), std::move(table_name), utils::data_type_traits<Type>::type(attr.size()), attr)
@@ -61,8 +62,10 @@ public:
   void name(const std::string& n);
   [[nodiscard]] std::string full_name() const;
   [[nodiscard]] std::string table_name() const;
+  void table_name(const std::string& tn);
   [[nodiscard]] int index() const;
   [[nodiscard]] const utils::field_attributes& attributes() const;
+  [[nodiscard]] utils::field_attributes& attributes();
   [[nodiscard]] bool is_nullable() const;
   [[nodiscard]] utils::basic_type type() const;
   [[nodiscard]] std::shared_ptr<attribute_definition> reference_column() const;
@@ -141,7 +144,7 @@ private:
  * @param type
  * @param attr Length of the column name
  * @param null_opt
- * @return A column object with given name
+ * @return A column object with a given name
  */
 attribute_definition make_column(const std::string &name, utils::basic_type type, utils::field_attributes attr = utils::null_attributes, null_option null_opt = null_option::NOT_NULL);
 
diff --git a/include/matador/object/attribute_definition_generator.hpp b/include/matador/object/attribute_definition_generator.hpp
index ca3ad96..32126f3 100644
--- a/include/matador/object/attribute_definition_generator.hpp
+++ b/include/matador/object/attribute_definition_generator.hpp
@@ -1,13 +1,13 @@
 #ifndef QUERY_COLUMN_DEFINITION_GENERATOR_HPP
 #define QUERY_COLUMN_DEFINITION_GENERATOR_HPP
 
-#include "attribute_definition.hpp"
+#include "matador/object/attribute_definition.hpp"
 
 #include "matador/utils/access.hpp"
 #include "matador/utils/data_type_traits.hpp"
 #include "matador/utils/error.hpp"
 #include "matador/utils/field_attributes.hpp"
-#include "matador/utils/foreign_attributes.hpp"
+
 
 #include <memory>
 #include <typeindex>
@@ -54,13 +54,13 @@ private:
 
 class attribute_definition_generator final {
 private:
-  attribute_definition_generator(std::vector<attribute_definition> &columns, const schema &repo);
+  attribute_definition_generator(std::vector<attribute_definition> &columns, schema &repo);
 
 public:
   ~attribute_definition_generator() = default;
 
   template < class Type >
-  static std::vector<attribute_definition> generate(const schema &repo)
+  static std::vector<attribute_definition> generate(schema &repo)
   {
     std::vector<attribute_definition> columns;
     attribute_definition_generator gen(columns, repo);
@@ -69,6 +69,14 @@ public:
     return columns;
   }
 
+  template < class Type >
+  static std::vector<attribute_definition> generate(const Type& obj, schema &repo) {
+    std::vector<attribute_definition> columns;
+    attribute_definition_generator gen(columns, repo);
+    access::process(gen, obj);
+    return columns;
+  }
+
   template < class V >
   void on_primary_key(const char *, V &x, std::enable_if_t<std::is_integral_v<V> && !std::is_same_v<bool, V>>* = nullptr);
   void on_primary_key(const char *id, std::string &pk, size_t size);
@@ -91,13 +99,19 @@ public:
 
   template <class Pointer>
   void on_foreign_key(const char *id, Pointer &x) {
-    if (const auto result = determine_foreign_ref(std::type_index(typeid(typename Pointer::value_type)))) {
-      if (x.empty()) {
-        typename Pointer::value_type temp_val;
-        columns_.push_back(fk_column_generator_.generate(id, temp_val, *result));
-      } else {
-        columns_.push_back(fk_column_generator_.generate(id, *x, *result));
-      }
+    std::shared_ptr<attribute_definition> ref_column;
+    std::type_index ti = typeid(typename Pointer::value_type);
+    if (const auto result = determine_foreign_ref(std::type_index(ti))) {
+        ref_column = *result;
+    } else {
+        ref_column = std::make_shared<attribute_definition>();
+        insert_missing_reference_column(ti, ref_column);
+    }
+    if (x.empty()) {
+      typename Pointer::value_type temp_val;
+      columns_.push_back(fk_column_generator_.generate(id, temp_val, ref_column));
+    } else {
+      columns_.push_back(fk_column_generator_.generate(id, *x, ref_column));
     }
   }
   template<class ContainerType>
@@ -109,11 +123,12 @@ public:
 
 private:
   [[nodiscard]] utils::result<std::shared_ptr<attribute_definition>, utils::error> determine_foreign_ref(const std::type_index &ti) const;
+  void insert_missing_reference_column(const std::type_index &ti, std::shared_ptr<attribute_definition> ref_column) const;
 
 private:
   size_t index_ = 0;
   std::vector<attribute_definition> &columns_;
-  const schema &repo_;
+  schema &repo_;
 
   fk_attribute_generator fk_column_generator_;
 };
diff --git a/include/matador/object/basic_object_info.hpp b/include/matador/object/basic_object_info.hpp
index 06e4589..bbc28ff 100644
--- a/include/matador/object/basic_object_info.hpp
+++ b/include/matador/object/basic_object_info.hpp
@@ -49,13 +49,12 @@ public:
   [[nodiscard]] bool endpoints_empty() const;
 
 protected:
-  basic_object_info(std::shared_ptr<schema_node> node, std::type_index type_index, utils::identifier &&pk, std::shared_ptr<attribute_definition> &&pk_column, object_definition &&definition);
-  basic_object_info(std::shared_ptr<schema_node> node, std::type_index type_index, utils::identifier &&pk, std::shared_ptr<attribute_definition> &&pk_column);
+  basic_object_info(std::shared_ptr<schema_node> node, std::type_index type_index, utils::identifier &&pk, const std::shared_ptr<attribute_definition> &pk_column, object_definition &&definition);
+  basic_object_info(std::shared_ptr<schema_node> node, std::type_index type_index, utils::identifier &&pk, const std::shared_ptr<attribute_definition> &pk_column);
   basic_object_info(std::shared_ptr<schema_node> node, std::type_index type_index, object_definition &&definition);
 
 protected:
   std::shared_ptr<schema_node> node_;            /**< prototype node of the represented object type */
-  std::type_index type_index_;   /**< type index of the represented object type */
   object_definition definition_;
   std::optional<utils::identifier> identifier_;
   std::shared_ptr<attribute_definition> pk_column_;
diff --git a/include/matador/object/object_info.hpp b/include/matador/object/object_info.hpp
index ad08f1e..eba9bdf 100644
--- a/include/matador/object/object_info.hpp
+++ b/include/matador/object/object_info.hpp
@@ -13,23 +13,23 @@ public:
   using create_func = std::function<std::unique_ptr<Type>()>;
 
   object_info(const std::shared_ptr<schema_node>& node,
-              std::shared_ptr<attribute_definition> &&ref_column)
-  : basic_object_info(node, typeid(Type), {}, std::move(ref_column), {})
+              const std::shared_ptr<attribute_definition> &ref_column)
+  : basic_object_info(node, typeid(Type), {}, ref_column, {})
   , creator_([]{return std::make_unique<Type>(); }){
   }
   object_info(const std::shared_ptr<schema_node>& node,
               utils::identifier &&pk,
-              std::shared_ptr<attribute_definition> &&ref_column,
+              const std::shared_ptr<attribute_definition> &ref_column,
               object_definition &&definition)
-  : basic_object_info(node, typeid(Type), std::move(pk), std::move(ref_column), std::move(definition))
+  : basic_object_info(node, typeid(Type), std::move(pk), ref_column, std::move(definition))
   , creator_([]{return std::make_unique<Type>(); }){
   }
   object_info(const std::shared_ptr<schema_node>& node,
               utils::identifier &&pk,
-              std::shared_ptr<attribute_definition> &&ref_column,
+              const std::shared_ptr<attribute_definition> &ref_column,
               object_definition &&definition,
               create_func&& creator)
-  : basic_object_info(node, typeid(Type), std::move(pk), std::move(ref_column), std::move(definition))
+  : basic_object_info(node, typeid(Type), std::move(pk), ref_column, std::move(definition))
   , creator_(std::move(creator)){
   }
   object_info(const std::shared_ptr<schema_node>& node,
diff --git a/include/matador/object/relation_completer.hpp b/include/matador/object/relation_completer.hpp
index f48ce45..852fe3f 100644
--- a/include/matador/object/relation_completer.hpp
+++ b/include/matador/object/relation_completer.hpp
@@ -129,17 +129,16 @@ void relation_completer<Type>::on_has_many(const char *id, CollectionType &,
     if (const auto endpoint = nodes_.top()->info().find_relation_endpoint(typeid(relation_value_type)); endpoint == nodes_.top()->info().endpoint_end()) {
         // Endpoint was not found
         log_.debug("node '%s' has has many foreign keys '%s' mapped by '%s'", nodes_.top()->name().c_str(), id, join_column);
-        const auto node = schema_node::make_relation_node<relation_value_type>(
+        result = schema_node::make_relation_node<relation_value_type>(
           schema_.schema(), id, [join_column] {
-            return std::make_unique<relation_value_type>(join_column, "id");
+            return std::make_unique<relation_value_type>("id", join_column);
           });
-        result = schema_.attach_node(node);
         if (!result) {
             // Todo: throw internal error
             return;
         }
         const auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, nodes_.top());
-        const auto foreign_endpoint = std::make_shared<relation_endpoint>(join_column, relation_type::BELONGS_TO, node);
+        const auto foreign_endpoint = std::make_shared<relation_endpoint>(join_column, relation_type::BELONGS_TO, result.value());
         nodes_.top()->info_->register_relation_endpoint(typeid(value_type), local_endpoint);
         foreign_endpoint->node_->info_->register_relation_endpoint(nodes_.top()->type_index(), foreign_endpoint);
         link_relation_endpoints(local_endpoint, foreign_endpoint);
@@ -171,18 +170,17 @@ void relation_completer<Type>::on_has_many(const char *id, CollectionType &, con
   using value_type = typename CollectionType::value_type;
   using relation_value_type = many_to_relation<Type, value_type>;
 
-  const auto node = schema_node::make_relation_node<relation_value_type>(
+  const auto result = schema_node::make_relation_node<relation_value_type>(
     schema_.schema(), id, [join_column] {
       return std::make_unique<relation_value_type>(join_column, "value");
     });
 
-  const auto result = schema_.attach_node(node);
   if (!result) {
     // Todo: throw internal exception
   }
 
   const auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, nodes_.top());
-  const auto foreign_endpoint = std::make_shared<relation_endpoint>(join_column, relation_type::BELONGS_TO, node);
+  const auto foreign_endpoint = std::make_shared<relation_endpoint>(join_column, relation_type::BELONGS_TO, result.value());
   nodes_.top()->info_->register_relation_endpoint(typeid(value_type), local_endpoint);
   foreign_endpoint->node_->info_->register_relation_endpoint(nodes_.top()->type_index(), foreign_endpoint);
   link_relation_endpoints(local_endpoint, foreign_endpoint);
@@ -210,13 +208,18 @@ void relation_completer<Type>::on_has_many_to_many(const char *id,
     }
     link_relation_endpoints(local_endpoint, it->second);
   } else {
-    // Relation not not found.
+    // Relation not found.
     auto creator = [join_column, inverse_join_column] {
       return std::make_unique<relation_value_type>(join_column, inverse_join_column);
     };
 
-    auto node = schema_node::make_relation_node<relation_value_type>(schema_.schema(), id, std::move(creator));
+    result = schema_node::make_relation_node<relation_value_type>(schema_.schema(), id, std::move(creator));
+    if (!result) {
+      // Todo: throw internal error
+      return;
+    }
 
+    auto& node = result.value();
     auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, nodes_.top());
     auto join_endpoint = std::make_shared<relation_endpoint>(join_column, relation_type::BELONGS_TO, node);
     auto inverse_join_endpoint = std::make_shared<relation_endpoint>(inverse_join_column, relation_type::BELONGS_TO,
@@ -226,11 +229,6 @@ void relation_completer<Type>::on_has_many_to_many(const char *id,
     link_relation_endpoints(local_endpoint, join_endpoint);
     node->info_->register_relation_endpoint(typeid(typename CollectionType::value_type::value_type),
                                             inverse_join_endpoint);
-    result = schema_.attach_node(node);
-    if (!result) {
-      // Todo: throw internal error
-      return;
-    }
   }
 }
 
diff --git a/include/matador/object/schema.hpp b/include/matador/object/schema.hpp
index b2514fd..6737231 100644
--- a/include/matador/object/schema.hpp
+++ b/include/matador/object/schema.hpp
@@ -40,11 +40,11 @@ public:
   [[nodiscard]] utils::result<void, utils::error> attach(const std::string &name, const std::string &parent = "") {
       if (const auto it = nodes_by_type_.find(typeid(Type)); it == nodes_by_type_.end() ) {
           auto node = schema_node::make_node<Type>(*this, name);
-          foreign_node_completer::complete<Type>(node);
-          relation_completer<Type>::complete(node);
           if (auto result = attach_node(node, parent); !result) {
               return utils::failure(result.err());
           }
+          foreign_node_completer::complete<Type>(node);
+          relation_completer<Type>::complete(node);
       } else if (!has_node(name)) {
           it->second->update_name(name);
           nodes_by_name_[name] = it->second;
@@ -142,7 +142,7 @@ public:
     return utils::ok(basic_object_info_ref{result.value()->info()});
   }
 
-  [[nodiscard]] utils::result<std::shared_ptr<attribute_definition>, utils::error> reference(
+  [[nodiscard]] utils::result<std::shared_ptr<attribute_definition>, utils::error> reference_column(
     const std::type_index &type_index) const;
 
   void dump(std::ostream &os) const;
@@ -169,7 +169,8 @@ private:
 
 private:
   friend class internal::shadow_schema;
-  friend class foreign_node_completer;
+  friend class schema_node;
+  friend class attribute_definition_generator;
 
   std::string name_;
   std::shared_ptr<schema_node> root_;
@@ -177,6 +178,8 @@ private:
   t_node_map nodes_by_name_;
   t_type_index_node_map nodes_by_type_;
   logger::logger log_;
+
+  std::unordered_map<std::type_index, std::shared_ptr<attribute_definition> > missing_references_;
 };
 }
 
diff --git a/include/matador/object/schema_node.hpp b/include/matador/object/schema_node.hpp
index e268bde..662c8cb 100644
--- a/include/matador/object/schema_node.hpp
+++ b/include/matador/object/schema_node.hpp
@@ -18,14 +18,15 @@ public:
 
   template < typename Type >
   static std::shared_ptr<schema_node> make_node(object::schema& tree, const std::string& name) {
-    auto node = std::shared_ptr<schema_node>(new schema_node(tree, name));
+    auto node = std::shared_ptr<schema_node>(new schema_node(tree, name, typeid(Type)));
 
     primary_key_resolver resolver;
     auto pk_info = resolver.resolve<Type>();
+    auto ref_column = determine_reference_column(typeid(Type), name, pk_info, tree);
     auto info = std::make_unique<object_info<Type>>(
       node,
       std::move(pk_info.pk),
-      std::make_shared<attribute_definition>(pk_info.pk_column_name, name, pk_info.type, utils::constraints::FOREIGN_KEY),
+      ref_column,
       object_definition{attribute_definition_generator::generate<Type>(tree)},
       []{ return std::make_unique<Type>(); }
     );
@@ -35,17 +36,21 @@ public:
   }
 
   template < typename Type, typename CreatorFunc >
-  static std::shared_ptr<schema_node> make_relation_node(object::schema& tree, const std::string& name, CreatorFunc &&creator) {
-    auto node = std::shared_ptr<schema_node>(new schema_node(tree, name));
+  static utils::result<node_ptr, utils::error> make_relation_node(object::schema& tree, const std::string& name, CreatorFunc &&creator) {
+    const auto result = make_and_attach_node(tree, name, typeid(Type));
+    if (!result) {
+        return result;
+    }
 
+    auto obj = creator();
     auto info = std::make_unique<object_info<Type>>(
-        node,
-        object_definition{attribute_definition_generator::generate<Type>(tree)},
+        result.value(),
+        object_definition{attribute_definition_generator::generate(*obj, tree)},
         std::move(creator)
     );
-    node->info_ = std::move(info);
+    result.value()->info_ = std::move(info);
 
-    return node;
+    return result;
   }
 
   static std::shared_ptr<schema_node> make_null_node(schema& tree);
@@ -77,10 +82,17 @@ public:
 
 private:
   explicit schema_node(object::schema& tree);
-  schema_node(object::schema& tree, std::string name);
+  schema_node(object::schema& tree, const std::type_index& ti);
+  schema_node(object::schema& tree, std::string name, const std::type_index& ti);
 
   void unlink();
 
+  static utils::result<node_ptr, utils::error> make_and_attach_node(object::schema& tree, const std::string& name, const std::type_index& ti);
+  static std::shared_ptr<attribute_definition> determine_reference_column(const std::type_index& ti,
+                                                     const std::string& name,
+                                                     const primary_key_info& pk_info,
+                                                     object::schema& tree);
+
 private:
   friend class schema;
   template<typename Type>
@@ -89,6 +101,7 @@ private:
   friend class const_schema_node_iterator;
 
   object::schema &schema_;
+  std::type_index type_index_;
   std::unique_ptr<basic_object_info> info_;
 
   std::shared_ptr<schema_node> parent_;
diff --git a/include/matador/object/schema_node_iterator.hpp b/include/matador/object/schema_node_iterator.hpp
index 2bc64d9..1ca0149 100644
--- a/include/matador/object/schema_node_iterator.hpp
+++ b/include/matador/object/schema_node_iterator.hpp
@@ -11,9 +11,9 @@ class const_schema_node_iterator {
 public:
   using iterator_category = std::bidirectional_iterator_tag;
   using difference_type = std::ptrdiff_t;
-  using value_type = schema_node;
-  using pointer = value_type*;
-  using reference = value_type&;
+  using value_type = std::shared_ptr<schema_node>;
+  using pointer = schema_node*;
+  using reference = value_type;
 
   /**
    * Creates an empty iterator
@@ -28,7 +28,7 @@ public:
    *
    * @param node The schema node of the object
    */
-  explicit const_schema_node_iterator(std::shared_ptr<value_type> node);
+  explicit const_schema_node_iterator(const value_type& node);
 
   /**
    * Copy from a given const_object_view_iterator.
@@ -109,7 +109,7 @@ public:
    *
    * @return The iterators underlying node.
    */
-  const reference operator*() const;
+  reference operator*() const;
 
   /**
    * Returns the pointer to the node.
@@ -123,7 +123,7 @@ private:
   void decrement();
 
 private:
-  std::shared_ptr<value_type> node_;
+  value_type node_;
 };
 
 }
diff --git a/include/matador/utils/error.hpp b/include/matador/utils/error.hpp
index 95fbe54..54942b6 100644
--- a/include/matador/utils/error.hpp
+++ b/include/matador/utils/error.hpp
@@ -50,7 +50,7 @@ public:
   friend bool operator<(const error &lhs, const error &rhs);
   friend bool operator<(const error &lhs, const std::error_code &rhs);
 
-  // friend std::ostream& operator<<(std::ostream &out, const error &err);
+  friend std::ostream& operator<<(std::ostream &out, const error &err);
 
   [[nodiscard]] std::string message() const;
   [[nodiscard]] std::string category() const;
diff --git a/source/core/object/attribute_definition.cpp b/source/core/object/attribute_definition.cpp
index bb0569d..cbd9c5b 100644
--- a/source/core/object/attribute_definition.cpp
+++ b/source/core/object/attribute_definition.cpp
@@ -77,6 +77,10 @@ std::string attribute_definition::table_name() const {
   return table_;
 }
 
+void attribute_definition::table_name( const std::string& tn ) {
+    table_= tn;
+}
+
 int attribute_definition::index() const {
   return index_;
 }
@@ -85,6 +89,10 @@ const utils::field_attributes &attribute_definition::attributes() const {
   return attributes_;
 }
 
+utils::field_attributes& attribute_definition::attributes() {
+  return attributes_;
+}
+
 bool attribute_definition::is_nullable() const {
   return null_option_ == null_option::NULLABLE;
 }
diff --git a/source/core/object/attribute_definition_generator.cpp b/source/core/object/attribute_definition_generator.cpp
index 1a27b63..7e82537 100644
--- a/source/core/object/attribute_definition_generator.cpp
+++ b/source/core/object/attribute_definition_generator.cpp
@@ -3,7 +3,7 @@
 
 namespace matador::object {
 
-attribute_definition_generator::attribute_definition_generator(std::vector<object::attribute_definition> &columns, const schema &repo)
+attribute_definition_generator::attribute_definition_generator(std::vector<object::attribute_definition> &columns, schema &repo)
 : columns_(columns)
 , repo_(repo)
 {}
@@ -19,7 +19,11 @@ void attribute_definition_generator::on_revision(const char *id, uint64_t &rev)
 }
 
 utils::result<std::shared_ptr<attribute_definition>, utils::error> attribute_definition_generator::determine_foreign_ref(const std::type_index &ti) const {
-    return repo_.reference(ti);
+  return repo_.reference_column(ti);
+}
+
+void attribute_definition_generator::insert_missing_reference_column(const std::type_index& ti, std::shared_ptr<attribute_definition> ref_column) const {
+  repo_.missing_references_.insert({ti, ref_column});
 }
 
 void fk_attribute_generator::on_primary_key(const char *, std::string &, const size_t size)
diff --git a/source/core/object/basic_object_info.cpp b/source/core/object/basic_object_info.cpp
index 61cb13d..807e519 100644
--- a/source/core/object/basic_object_info.cpp
+++ b/source/core/object/basic_object_info.cpp
@@ -8,34 +8,31 @@ namespace matador::object {
 basic_object_info::basic_object_info(std::shared_ptr<schema_node> node,
                                      const std::type_index type_index,
                                      utils::identifier &&pk,
-                                     std::shared_ptr<attribute_definition> &&pk_column,
+                                     const std::shared_ptr<attribute_definition> &pk_column,
                                      object_definition &&definition)
 : node_(std::move(node))
-, type_index_(type_index)
 , definition_(std::move(definition))
 , identifier_(std::move(pk))
-, pk_column_(std::move(pk_column)) {
+, pk_column_(pk_column) {
 }
 
 basic_object_info::basic_object_info(std::shared_ptr<schema_node> node,
                                      const std::type_index type_index,
                                      utils::identifier &&pk,
-                                     std::shared_ptr<attribute_definition> &&pk_column)
+                                     const std::shared_ptr<attribute_definition> &pk_column)
 : node_(std::move(node))
-, type_index_(type_index)
 , identifier_(std::move(pk))
-, pk_column_(std::move(pk_column)) {
+, pk_column_(pk_column) {
 }
 
 basic_object_info::basic_object_info(std::shared_ptr<schema_node> node,
                                      const std::type_index type_index,
                                      object_definition &&definition)
 : node_(std::move(node))
-, type_index_(type_index)
 , definition_(std::move(definition)) {}
 
 std::type_index basic_object_info::type_index() const {
-  return type_index_;
+  return node_->type_index();
 }
 
 std::string basic_object_info::name() const {
diff --git a/source/core/object/schema.cpp b/source/core/object/schema.cpp
index a76b4dc..35deb42 100644
--- a/source/core/object/schema.cpp
+++ b/source/core/object/schema.cpp
@@ -53,7 +53,7 @@ bool schema::contains( const std::type_index& index ) const {
   return nodes_by_type_.count(index) > 0;
 }
 
-utils::result<std::shared_ptr<attribute_definition>, utils::error> schema::reference(const std::type_index &type_index) const {
+utils::result<std::shared_ptr<attribute_definition>, utils::error> schema::reference_column(const std::type_index &type_index) const {
   const auto result = find_node(type_index);
   if (result) {
     return utils::ok((*result)->info().reference_column());
@@ -64,8 +64,8 @@ utils::result<std::shared_ptr<attribute_definition>, utils::error> schema::refer
 
 void schema::dump(std::ostream &os) const {
   for (const auto &node : *this) {
-    os << "node [" << node.name() << "] (" << node.type_index().name() << ")\n";
-    for (auto it = node.info().endpoint_begin(); it != node.info().endpoint_end(); ++it) {
+    os << "node [" << node->name() << "] (" << node->type_index().name() << ")\n";
+    for (auto it = node->info().endpoint_begin(); it != node->info().endpoint_end(); ++it) {
       os << "  " << /*node.name() << "::" <<*/ it->second->field_name() << " (" << it->second->type_name() << ")";
       if (it->second->foreign_endpoint()) {
         os << " <---> " << it->second->foreign_endpoint()->node().name() << "::" << it->second->foreign_endpoint()->field_name() << " (" << it->second->foreign_endpoint()->type_name() << ")\n";
diff --git a/source/core/object/schema_node.cpp b/source/core/object/schema_node.cpp
index 32d01e3..1fb7e16 100644
--- a/source/core/object/schema_node.cpp
+++ b/source/core/object/schema_node.cpp
@@ -1,14 +1,22 @@
 #include <utility>
 
+#include "matador/object/schema.hpp"
 #include "matador/object/schema_node.hpp"
 
 namespace matador::object {
 schema_node::schema_node(object::schema &tree)
-: schema_(tree) {
+: schema_(tree)
+, type_index_(typeid(detail::null_type)){
 }
 
-schema_node::schema_node(object::schema &tree, std::string name)
+schema_node::schema_node(object::schema &tree, const std::type_index& ti)
 : schema_(tree)
+, type_index_(ti) {
+}
+
+schema_node::schema_node(object::schema &tree, std::string name, const std::type_index& ti)
+: schema_(tree)
+, type_index_(ti)
 , first_child_(std::shared_ptr<schema_node>(new schema_node(tree)))
 , last_child_(std::shared_ptr<schema_node>(new schema_node(tree)))
 , name_(std::move(name)) {
@@ -28,7 +36,7 @@ std::string schema_node::name() const {
 }
 
 std::type_index schema_node::type_index() const {
-  return info_->type_index();
+  return type_index_;
 }
 
 const basic_object_info &schema_node::info() const {
@@ -37,7 +45,7 @@ const basic_object_info &schema_node::info() const {
 
 void schema_node::update_name(const std::string& name) {
   name_ = name;
-  info_->reference_column()->name(name);
+  info_->reference_column()->table_name(name);
 }
 
 const object::schema& schema_node::schema() const {
@@ -50,7 +58,7 @@ bool schema_node::has_children() const {
 
 schema_node::node_ptr schema_node::next() const {
   // if we have a child, child is the next iterator to return
-  // (if we don't do iterate over the siblings)
+  // (if we don't iterate over the siblings)
   if (first_child_ && first_child_->next_sibling_ != last_child_) {
     return first_child_->next_sibling_;
   }
@@ -65,7 +73,7 @@ schema_node::node_ptr schema_node::next() const {
 }
 
 schema_node::node_ptr schema_node::prev() const {
-  // if node has a previous sibling, we set it
+  // if the node has a previous sibling, we set it
   // as our next iterator. then we check if there
   // are last children. if so, we set the last-last
   // child as our iterator
@@ -87,4 +95,30 @@ void schema_node::unlink() {
   next_sibling_.reset();
   previous_sibling_.reset();
 }
+
+utils::result<schema_node::node_ptr, utils::error> schema_node::make_and_attach_node(object::schema& tree, const std::string& name, const std::type_index& ti) {
+    const auto node = std::shared_ptr<schema_node>(new schema_node(tree, name, ti));
+
+    return tree.attach_node(node, "");
+}
+
+std::shared_ptr<attribute_definition> schema_node::determine_reference_column(const std::type_index& ti, const std::string& name, const primary_key_info& pk_info, object::schema& tree) {
+    const auto it = tree.missing_references_.find(ti);
+    if (it == tree.missing_references_.end()) {
+        return std::make_shared<attribute_definition>(pk_info.pk_column_name, name, pk_info.type, utils::constraints::FOREIGN_KEY);
+    }
+
+    auto ref_column = it->second;
+    tree.missing_references_.erase(it);
+    ref_column->name(pk_info.pk_column_name);
+    ref_column->table_name(name);
+    ref_column->type(pk_info.type);
+    ref_column->attributes() = utils::constraints::FOREIGN_KEY;
+
+    if (name.empty()) {
+      tree.missing_references_.insert({ti, ref_column});
+    }
+
+    return ref_column;
+}
 }
diff --git a/source/core/object/schema_node_iterator.cpp b/source/core/object/schema_node_iterator.cpp
index 82f1e97..cd522f1 100644
--- a/source/core/object/schema_node_iterator.cpp
+++ b/source/core/object/schema_node_iterator.cpp
@@ -4,8 +4,8 @@
 
 namespace matador::object {
 
-const_schema_node_iterator::const_schema_node_iterator(std::shared_ptr<value_type> node)
-: node_(std::move(node))
+const_schema_node_iterator::const_schema_node_iterator(const value_type& node)
+: node_(node)
 {}
 
 bool const_schema_node_iterator::operator==(const const_schema_node_iterator &i) const
@@ -25,7 +25,7 @@ const_schema_node_iterator& const_schema_node_iterator::operator++()
 }
 
 const_schema_node_iterator const_schema_node_iterator::operator++( int ) {
-  const std::shared_ptr<value_type> tmp = node_;
+  const value_type tmp = node_;
   increment();
   return const_schema_node_iterator(tmp);
 }
@@ -38,7 +38,7 @@ const_schema_node_iterator& const_schema_node_iterator::operator--()
 
 const_schema_node_iterator const_schema_node_iterator::operator--(int)
 {
-  const std::shared_ptr<value_type> tmp = node_;
+  const value_type tmp = node_;
   decrement();
   return const_schema_node_iterator(tmp);
 }
@@ -50,7 +50,7 @@ const_schema_node_iterator::pointer const_schema_node_iterator::operator->() con
 
 const_schema_node_iterator::reference const_schema_node_iterator::operator*() const
 {
-  return *node_;
+  return node_;
 }
 
 const_schema_node_iterator::pointer const_schema_node_iterator::get() const
diff --git a/source/core/utils/error.cpp b/source/core/utils/error.cpp
index baf4c7b..9ae4bbe 100644
--- a/source/core/utils/error.cpp
+++ b/source/core/utils/error.cpp
@@ -81,9 +81,12 @@ bool operator<(const error &lhs, const std::error_code &rhs) {
   return lhs.ec_ < rhs;
 }
 
-// std::ostream & operator<<(std::ostream &out, const error &err) {
-  // out << err.ec_ << " " << err.ec_.message();
-  // return out;
-// }
+std::ostream & operator<<(std::ostream &out, const error &err) {
+  out << err.ec_ << " " << err.ec_.message() << "\n";
+  for (const auto & [key, value] : err.error_infos_) {
+    out << "  " << key << ": " << value << "\n";
+  }
+  return out;
+}
 
 }
diff --git a/source/orm/orm/session.cpp b/source/orm/orm/session.cpp
index 0276ecc..24d9f53 100644
--- a/source/orm/orm/session.cpp
+++ b/source/orm/orm/session.cpp
@@ -18,10 +18,15 @@ session::session(sql::connection_pool<sql::connection> &pool)
 , schema_(std::make_unique<object::schema>(dialect_.default_schema_name())){}
 
 utils::result<void, utils::error> session::create_schema() const {
+  std::vector<std::shared_ptr<object::schema_node>> relations_nodes;
   auto c = pool_.acquire();
-  for (const auto &t : *schema_) {
+  for (const auto &node : *schema_) {
+    // if (!node->info().has_primary_key()) {
+        // relations_nodes.push_back(node);
+        // continue;
+    // }
     auto result = query::query::create()
-      .table(t.name(), t.info().definition().columns())
+      .table(node->name(), node->info().definition().columns())
       .execute(*c);
     if ( !result ) {
       return utils::failure(result.err());
diff --git a/source/orm/query/query_compiler.cpp b/source/orm/query/query_compiler.cpp
index 19efa79..4987254 100644
--- a/source/orm/query/query_compiler.cpp
+++ b/source/orm/query/query_compiler.cpp
@@ -276,7 +276,7 @@ void query_compiler::visit(internal::query_create_table_part &create_table_part)
   for (const auto &[column, reference_column]: context.foreign_contexts) {
     result += ", CONSTRAINT FK_" + create_table_part.table().name;
     result += "_" + column;
-    result += " FOREIGN KEY (" + column + ")";
+    result += " FOREIGN KEY (" + dialect_->prepare_identifier_string(column) + ")";
     result += " REFERENCES " + reference_column->table_name() + "(" + reference_column->name() + ")";
   }