finished relation completer

demo/CMakeLists.txt

@@ -13,3 +13,11 @@ target_link_libraries(sandbox PRIVATE
   ${CMAKE_DL_LIBS}
   ${SQLite3_LIBRARIES}
 )
+
+add_executable(work work.cpp)
+target_link_libraries(work PRIVATE
+  matador-core
+  matador-orm
+  ${CMAKE_DL_LIBS}
+  ${SQLite3_LIBRARIES}
+)

demo/recipe.hpp

@@ -0,0 +1,61 @@
+#ifndef QUERY_RECIPE_HPP
+#define QUERY_RECIPE_HPP
+
+#include "matador/utils/access.hpp"
+#include "matador/utils/foreign_attributes.hpp"
+
+#include "matador/object/collection.hpp"
+#include "matador/object/object_ptr.hpp"
+#include "matador/object/many_to_many_relation.hpp"
+
+#include <string>
+
+namespace demo {
+
+struct recipe;
+struct ingredient
+{
+  unsigned int id{};
+  std::string name;
+  matador::object::collection<matador::object::object_ptr<recipe>> recipes{};
+
+  ingredient()= default;
+  ingredient(const unsigned int id, std::string name)
+    : id(id), name(std::move(name)) {}
+
+  template<class Operator>
+  void process(Operator &op) {
+    namespace field = matador::access;
+    field::primary_key(op, "id", id);
+    field::attribute(op, "name", name, 255);
+    field::has_many_to_many(op, "recipe_ingredients", recipes, "ingredient_id", "recipe_id", matador::utils::fetch_type::EAGER);
+  }
+};
+
+struct recipe
+{
+  unsigned int id{};
+  std::string name;
+  matador::object::collection<matador::object::object_ptr<ingredient>> ingredients{};
+
+  recipe()= default;
+  recipe(const unsigned int id, std::string name)
+  : id(id), name(std::move(name)) {}
+
+  template<class Operator>
+  void process(Operator &op) {
+    namespace field = matador::access;
+    field::primary_key(op, "id", id);
+    field::attribute(op, "name", name, 255);
+    field::has_many_to_many(op, "recipe_ingredients", ingredients, matador::utils::fetch_type::LAZY);
+  }
+};
+
+class recipe_ingredient : public matador::object::many_to_many_relation<recipe, ingredient> {
+public:
+  recipe_ingredient() : many_to_many_relation("recipe_id", "ingredient_id") {}
+};
+
+}
+
+#endif //QUERY_RECIPE_HPP

demo/sandbox.cpp

@@ -4,6 +4,7 @@
 
 #include "author.hpp"
 #include "book.hpp"
+#include "recipe.hpp"
 
 #include <iostream>
 
@@ -54,6 +55,51 @@
  *    - set foreign endpoint of (2) to endpoint (1)
  *  - check relation endpoints...
  */
+
+namespace demo {
+struct names {
+    unsigned int id{};
+    std::vector<std::string> names_list;
+
+    template<typename Operator>
+    void process(Operator &op) {
+        namespace field = matador::access;
+        field::primary_key( op, "id", id );
+        field::has_many(op, "name_list", names_list, "names_id", matador::utils::fetch_type::EAGER);
+    }
+};
+
+struct user;
+struct profile {
+    unsigned int id{};
+    std::string first_name;
+    std::string last_name;
+    matador::object::object_ptr<user> user;
+
+    template<typename Operator>
+    void process(Operator &op) {
+        namespace field = matador::access;
+        field::primary_key( op, "id", id );
+        field::attribute( op, "first_name", first_name, 255 );
+        field::attribute( op, "last_name", last_name, 255 );
+        field::belongs_to( op, "user_id", user, matador::utils::default_foreign_attributes );
+    }
+};
+struct user {
+    unsigned int id{};
+    std::string username;
+    matador::object::object_ptr<profile> profile;
+
+    template<typename Operator>
+    void process(Operator &op) {
+        namespace field = matador::access;
+        field::primary_key( op, "id", id );
+        field::attribute( op, "username", username, 255 );
+        field::has_one(op, "profile_id", profile, matador::utils::default_foreign_attributes );
+    }
+};
+}
+
 using namespace demo;
 using namespace matador;
 
@@ -62,6 +108,15 @@ int main() {
   logger::add_log_sink(logger::create_stdout_sink());
 
   {
+    // has_many with builtin-type
+    object::schema schema;
+
+    auto result = schema.attach<names>("names");
+
+    schema.dump(std::cout);
+  }
+  {
+    // has_many to belongs_to
     object::schema schema;
 
     auto result = schema.attach<author>("authors")
@@ -70,6 +125,7 @@ int main() {
     schema.dump(std::cout);
   }
   {
+    // belongs_to to has_many
     object::schema schema;
 
     auto result = schema.attach<book>("books")
@@ -77,4 +133,40 @@ int main() {
 
     schema.dump(std::cout);
   }
+  {
+    // has_many_to_many (with join columns first)
+    object::schema schema;
+
+    auto result = schema.attach<ingredient>("ingredients")
+        .and_then([&schema] { return schema.attach<recipe>("recipes"); });
+
+    schema.dump(std::cout);
+  }
+  {
+    // has_many_to_many (with join columns last)
+    object::schema schema;
+
+    auto result = schema.attach<recipe>("recipes")
+        .and_then([&schema] { return schema.attach<ingredient>("ingredients"); });
+
+    schema.dump(std::cout);
+  }
+  {
+    // belongs_to to has_one
+    object::schema schema;
+
+    auto result = schema.attach<profile>("profiles")
+        .and_then([&schema] { return schema.attach<user>("users"); });
+
+    schema.dump(std::cout);
+  }
+  {
+    // has_one to belongs_to
+    object::schema schema;
+
+    auto result = schema.attach<user>("users")
+        .and_then([&schema] { return schema.attach<profile>("profiles"); });
+
+    schema.dump(std::cout);
+  }
 }

demo/work.cpp

@@ -11,17 +11,38 @@
 #include "work/admin/UserSession.hpp"
 
 #include "work/jobs/Job.hpp"
-#include "work/jobs/Task.hpp""
+#include "work/jobs/Task.hpp"
 #include "work/jobs/Payload.hpp"
 #include "work/jobs/IdPayload.hpp"
 #include "work/jobs/IdListPayload.hpp"
 
+#include "matador/utils/default_type_traits.hpp"
 #include "matador/object/schema.hpp"
 
 #include "matador/sql/connection.hpp"
 
 #include "matador/orm/session.hpp"
 
+template <> struct matador::utils::data_type_traits<work::core::timestamp, void> {
+    static basic_type type(std::size_t /*size*/) { return basic_type::type_uint64; }
+    static void read_value(attribute_reader &reader, const char *id, size_t index, nullptr_t &/*value*/) {
+
+    }
+    static void bind_value(attribute_writer &binder, size_t index, nullptr_t &/*value*/) {
+
+    }
+};
+
+template <> struct matador::utils::data_type_traits<work::core::UserInfo, void> {
+    static basic_type type(std::size_t /*size*/) { return basic_type::type_uint64; }
+    static void read_value(attribute_reader &reader, const char *id, size_t index, nullptr_t &/*value*/) {
+
+    }
+    static void bind_value(attribute_writer &binder, size_t index, nullptr_t &/*value*/) {
+
+    }
+};
+
 using namespace matador;
 using namespace work::models;
 
@@ -51,36 +72,38 @@ using namespace work::models;
 int main() {
     object::schema schema("Administration");
 
-    auto result = schema.attach<admin::CollectionCenter>("collection_center")
+    auto result = schema.attach<admin::CollectionCenter>("collection_centers")
         .and_then([&schema] { return schema.attach<admin::UserDirectory>("user_directories"); })
         .and_then([&schema] { return schema.attach<admin::LdapGroupSchemaSettings>("ldap_group_schema_settings"); })
         .and_then([&schema] { return schema.attach<admin::LdapImportSettings>("ldap_import_settings"); })
         .and_then([&schema] { return schema.attach<admin::LdapUserSchemaSettings>("ldap_user_schema_settings"); })
-        .and_then([&schema] { return schema.attach<admin::UserDirectory, admin::InternalUserDirectory>("internal_user_directories"); })
+        .and_then([&schema] { return schema.attach<admin::InternalUserDirectory, admin::UserDirectory>("internal_user_directories"); })
-        .and_then([&schema] { return schema.attach<admin::UserDirectory, admin::LdapUserDirectory>("ldap_user_directories"); } )
+        .and_then([&schema] { return schema.attach<admin::LdapUserDirectory, admin::UserDirectory>("ldap_user_directories"); } )
         .and_then([&schema] { return schema.attach<admin::LoginHistory>("login_histories"); })
         .and_then([&schema] { return schema.attach<admin::Scenario>("scenarios"); })
         .and_then([&schema] { return schema.attach<admin::User>("users"); })
         .and_then([&schema] { return schema.attach<admin::UserSession>("user_sessions"); })
         .and_then([&schema] { return schema.attach<jobs::Job>("jobs"); })
         .and_then([&schema] { return schema.attach<jobs::Payload>("payloads"); })
-        .and_then([&schema] { return schema.attach<jobs::Payload, jobs::IdPayload>("id_list_payloads"); })
+        .and_then([&schema] { return schema.attach<jobs::IdPayload, jobs::Payload>("id_list_payloads"); })
-        .and_then([&schema] { return schema.attach<jobs::Payload, jobs::IdListPayload>("id_payloads"); })
+        .and_then([&schema] { return schema.attach<jobs::IdListPayload, jobs::Payload>("id_payloads"); })
         .and_then([&schema] { return schema.attach<jobs::Task>("tasks"); });
 
     if (!result.is_ok()) {
+        std::cout << "error: " << result.err().message() << std::endl;
         return 0;
     }
 
-    const std::string dns{"sqlite://demo.db"};
+    schema.dump(std::cout);
-    sql::connection c(dns);
+    // const std::string dns{"sqlite://demo.db"};
-
+    // sql::connection c(dns);
-    result = c.open();
+    //
-
+    // result = c.open();
-    // orm::session s()
+    //
-    if (!result.is_ok()) {
+    // // orm::session s()
-        return 0;
+    // if (!result.is_ok()) {
-    }
+    //     return 0;
+    // }
 
 
     return 0;

demo/work/admin/CollectionCenter.hpp

@@ -4,6 +4,7 @@
 #include "../core/Model.hpp"
 
 #include "matador/object/collection.hpp"
+#include "matador/object/object_ptr.hpp"
 
 #include "matador/utils/base_class.hpp"
 #include "matador/utils/enum_mapper.hpp"
@@ -29,7 +30,7 @@ struct CollectionCenter : core::Model {
     std::string name;
     matador::utils::blob symbol;
     CollectionCenterType type{CollectionCenterType::NoType};
-    matador::object::collection<User> users;
+    matador::object::collection<matador::object::object_ptr<User>> users;
 
     template<typename Operator>
     void process( Operator& op ) {

demo/work/admin/LoginHistory.hpp

@@ -7,7 +7,7 @@
 
 #include "../core/Model.hpp"
 
-#include "matador/object/object_ptr.hpp""
+#include "matador/object/object_ptr.hpp"
 
 #include "matador/utils/base_class.hpp"
 #include "matador/utils/enum_mapper.hpp"

demo/work/admin/Scenario.hpp

@@ -42,7 +42,7 @@ struct Scenario : core::Model {
     std::string description;
     matador::utils::blob symbol;
     ScenarioState state{ScenarioState::InvalidState};
-    matador::object::collection<CollectionCenter> collection_center;
+    matador::object::collection<matador::object::object_ptr<CollectionCenter>> collection_center;
 
     template<typename Operator>
     void process( Operator& op ) {

demo/work/admin/User.hpp

@@ -6,7 +6,7 @@
 #include "../core/Model.hpp"
 #include "../core/Types.hpp"
 
-#include "matador/object/object_ptr.hpp""
+#include "matador/object/object_ptr.hpp"
 
 #include "matador/utils/base_class.hpp"
 #include "matador/utils/types.hpp"

demo/work/admin/UserSession.hpp

@@ -8,7 +8,7 @@
 #include "../core/Model.hpp"
 #include "../core/Types.hpp"
 
-#include "matador/object/object_ptr.hpp""
+#include "matador/object/object_ptr.hpp"
 
 #include "matador/utils/base_class.hpp"
 

demo/work/jobs/IdListPayload.hpp

@@ -5,6 +5,8 @@
 
 #include "matador/object/collection.hpp"
 
+#include "matador/utils/foreign_attributes.hpp"
+
 namespace work::models::jobs {
 struct IdListPayload : Payload {
     matador::object::collection<unsigned long long> ids;
@@ -12,7 +14,7 @@ struct IdListPayload : Payload {
     void process( Operator& op ) {
         namespace field = matador::access;
         field::process( op, *matador::base_class<Payload>( this ) );
-        field::has_many( op, "payload_ids", ids );
+        field::has_many( op, "payload_ids", ids, "payload_id", matador::utils::default_foreign_attributes );
     }
 };
 }

demo/work/jobs/Job.hpp

@@ -35,7 +35,7 @@ struct Job : core::Model {
         field::attribute( op, "state", state );
         field::attribute( op, "mode", mode );
         field::attribute( op, "created_at", created_at );
-        field::belongs_to( op, "payload", payload, matador::utils::default_foreign_attributes );
+        field::has_one(op, "payload", payload, matador::utils::default_foreign_attributes );
         field::belongs_to( op, "task", task, matador::utils::default_foreign_attributes );
         field::attribute( op, "user_info", user_info );
     }

demo/work/jobs/Payload.hpp

@@ -6,13 +6,17 @@
 #include "matador/utils/base_class.hpp"
 
 namespace work::models::jobs {
+struct Job;
 struct Payload : core::Model {
     std::string type;
+    matador::object::object_ptr<Job> job;
+
     template<typename Operator>
     void process( Operator& op ) {
         namespace field = matador::access;
         field::process( op, *matador::base_class<Model>( this ) );
         field::attribute( op, "type", type, 255 );
+        field::belongs_to( op, "job", job, matador::utils::default_foreign_attributes );
     }
 };
 }

include/matador/object/join_columns_collector.hpp

@@ -0,0 +1,51 @@
+#ifndef JOIN_COLUMNS_COLLECTOR_HPP
+#define JOIN_COLUMNS_COLLECTOR_HPP
+
+#include "matador/utils/access.hpp"
+#include "matador/utils/field_attributes.hpp"
+
+#include <string>
+
+namespace matador::object {
+struct join_columns {
+  std::string join_column;
+  std::string inverse_join_column;
+};
+
+class join_columns_collector final {
+public:
+    template<class Type>
+    join_columns collect() {
+        join_columns_ = {};
+        Type obj;
+
+        access::process(*this, obj);
+
+        return join_columns_;
+    }
+    template < class V >
+    void on_primary_key(const char * /*id*/, V &, std::enable_if_t<std::is_integral_v<V> && !std::is_same_v<bool, V>>* = nullptr) {}
+    static void on_primary_key(const char * /*id*/, std::string &, size_t) {}
+    static void on_revision(const char * /*id*/, unsigned long long &/*rev*/) {}
+    template<typename Type>
+    static void on_attribute(const char * /*id*/, Type &, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
+    template<class Pointer>
+    static void on_belongs_to(const char * /*id*/, Pointer &obj, const utils::foreign_attributes &attr) {}
+    template<class Pointer>
+    static void on_has_one(const char * /*id*/, Pointer &obj, const utils::foreign_attributes &attr) {}
+    template<class ContainerType>
+    static void on_has_many(ContainerType &, const char *join_column, const utils::foreign_attributes &attr) {}
+    template<class ContainerType>
+    void on_has_many_to_many(const char * /*id*/, ContainerType &/*c*/, const char *join_column, const char *inverse_join_column, const utils::foreign_attributes &/*attr*/) {
+        join_columns_.join_column = join_column;
+        join_columns_.inverse_join_column = inverse_join_column;
+    }
+    template<class ContainerType>
+    static void on_has_many_to_many(const char * /*id*/, ContainerType &/*c*/, const utils::foreign_attributes &/*attr*/) {}
+
+private:
+    join_columns join_columns_;
+};
+}
+
+#endif //JOIN_COLUMNS_COLLECTOR_HPP

include/matador/object/schema.hpp

@@ -2,6 +2,8 @@
 #define SCHEMA_HPP
 
 #include "matador/logger/log_manager.hpp"
+
+#include "matador/object/join_columns_collector.hpp"
 #include "matador/object/many_to_many_relation.hpp"
 #include "matador/object/primary_key_resolver.hpp"
 #include "matador/object/error_code.hpp"
@@ -105,8 +107,8 @@ public:
   template<class CollectionType>
   void on_has_many_to_many(const char *id, CollectionType &collection, const char *join_column,
                            const char *inverse_join_column, const utils::foreign_attributes &attr);
-  template<class ContainerType>
+  template<class CollectionType>
-  void on_has_many_to_many(const char *id, ContainerType &collection, const utils::foreign_attributes &attr);
+  void on_has_many_to_many(const char *id, CollectionType &collection, const utils::foreign_attributes &attr);
 
 private:
   explicit relation_completer(const std::shared_ptr<schema_node> &node)
@@ -123,6 +125,7 @@ private:
   std::shared_ptr<schema_node> node_;
   schema &schema_;
   logger::logger log_;
+  join_columns_collector join_columns_collector_;
 };
 
 
@@ -140,9 +143,9 @@ public:
   template<typename Type>
   [[nodiscard]] utils::result<void, utils::error> attach(const std::string &name, const std::string &parent = "") {
     // if (has_node(name)) {
-    // return utils::failure(make_error(error_code::NodeAlreadyExists, "Node '" + name + "' already exists"));
+      // return utils::failure(make_error(error_code::NodeAlreadyExists, "Node '" + name + "' already exists"));
     // }
-    auto node = acquire_node<Type>(name);
+    auto node = schema_node::make_node<Type>(*this, name);
     relation_completer<Type>::complete(node);
     if (auto result = attach_node(node, parent); !result) {
       return utils::failure(result.err());
@@ -239,25 +242,11 @@ private:
   [[nodiscard]] utils::result<node_ptr, utils::error> find_node(const std::string &name) const;
   [[nodiscard]] utils::result<node_ptr, utils::error> find_node(const std::type_index &type_index) const;
 
-  template<typename Type>
-  node_ptr acquire_node(const std::string &name) {
-    if (const auto it = expected_node_map_.find(typeid(Type)); it != expected_node_map_.end()) {
-      const auto node = it->second;
-      expected_node_map_.erase(it);
-      node->update_name(name);
-
-      return node;
-    }
-
-    return schema_node::make_node<Type>(*this, name);
-  }
-
-
   [[nodiscard]] bool has_node(const std::string &name) const;
   [[nodiscard]] bool has_node(const std::type_index &index) const;
   [[nodiscard]] bool has_node(const std::type_index &index, const std::string &name) const;
 
-  static void push_back_child(const node_ptr &parent, const node_ptr &child);
+  static void insert_node(const node_ptr &parent, const node_ptr &child);
   void remove_node(const node_ptr &node);
 
 private:
@@ -269,7 +258,6 @@ private:
 
   t_node_map nodes_by_name_;
   t_type_index_node_map nodes_by_type_;
-  t_type_index_node_map expected_node_map_;
   logger::logger log_;
 };
 
@@ -330,70 +318,130 @@ template<typename Type>
 template<class CollectionType>
 void relation_completer<Type>::on_has_many(const char *id, CollectionType &, const char *join_column,
                                            const utils::foreign_attributes &,
-                                           std::enable_if_t<!is_object_ptr<typename CollectionType::value_type>::value>
+                                           std::enable_if_t<!is_object_ptr<typename CollectionType::value_type>::value>* /*unused*/) {
-                                           * /*unused*/) {
   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<many_to_many_relation<value_type, Type> >(
+  const auto node = schema_node::make_relation_node<relation_value_type>(
     schema_, id, [join_column] {
-      return new many_to_many_relation<value_type, Type>(join_column, "value");
+      return std::make_unique<relation_value_type>(join_column, "value");
     });
 
-  const auto result = schema_.attach<many_to_relation<Type, value_type> >(id);
+  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, node_);
+  const auto foreign_endpoint = std::make_shared<relation_endpoint>(join_column, relation_type::BELONGS_TO, node);
+  node_->info_->register_relation_endpoint(typeid(value_type), local_endpoint);
+  foreign_endpoint->node_->info_->register_relation_endpoint(node_->type_index(), foreign_endpoint);
+  link_relation_endpoints(local_endpoint, foreign_endpoint);
+}
+
+template<typename Type>
+template<class CollectionType>
+void relation_completer<Type>::on_has_many_to_many(const char *id,
+                                                   CollectionType &/*collection*/,
+                                                   const char *join_column,
+                                                   const char *inverse_join_column,
+                                                   const utils::foreign_attributes &/*attr*/) {
+  auto result = schema_.find_node(id);
+  if (result) {
+    const auto foreign_node = result.value();
+    const auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, node_);
+    node_->info_->register_relation_endpoint(typeid(CollectionType::value_type::value_type), local_endpoint);
+    const auto it = foreign_node->info_->find_relation_endpoint(node_->type_index());
+    if (it == foreign_node->info().endpoint_end()) {
+      // Todo: Throw error
+      return;
+    }
+    link_relation_endpoints(local_endpoint, it->second);
+  } else {
+    using relation_value_type = many_to_many_relation<typename CollectionType::value_type::value_type, Type>;
+    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_, id, std::move(creator));
+
+    auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, node_);
+    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, node);
+    node_->info_->register_relation_endpoint(typeid(CollectionType::value_type::value_type), local_endpoint);
+    node->info_->register_relation_endpoint(node_->type_index(), join_endpoint);
+    link_relation_endpoints(local_endpoint, join_endpoint);
+    node->info_->register_relation_endpoint(typeid(CollectionType::value_type::value_type), inverse_join_endpoint);
+    result = schema_.attach_node(node, "");
+    if (!result) {
+      // Todo: throw internal error
+      return;
+    }
+  }
 }
 
 template<typename Type>
 template<class CollectionType>
-void relation_completer<Type>::on_has_many_to_many(const char *id, CollectionType &/*collection*/,
+void relation_completer<Type>::on_has_many_to_many(const char *id,
-                                                   const char *join_column,
+                                                   CollectionType &/*collection*/,
-                                                   const char *inverse_join_column,
+                                                   const utils::foreign_attributes &/*attr*/) {
-                                                   const utils::foreign_attributes &attr) {
-  auto result = schema_.find_node(id);
-  if (result) {
-  } else {
-    //
-    // using relation_type = many_to_many_relation<typename CollectionType::value_type, Type>;
-    // auto creator = [join_column, inverse_join_column] {
-    //   return new many_to_many_relation<typename CollectionType::value_type, Type>(join_column, inverse_join_column);
-    // };
-
-    // auto node = schema_node::make_relation_node<relation_type>(schema_, id);
-
-    // schema_.attach_node(node, typeid(relation_type));
-  }
-}
-
-template<typename Type>
-template<class ContainerType>
-void relation_completer<Type>::on_has_many_to_many(const char *id, ContainerType &collection,
-                                                   const utils::foreign_attributes &attr) {
   auto result = schema_.find_node(id);
   if (!result) {
-    // using relation_type = many_to_many_relation<typename ContainerType::value_type, Type>;
+    const auto join_columns = join_columns_collector_.collect<typename CollectionType::value_type::value_type>();
-    // auto creator = [attr] {
+    using relation_value_type = many_to_many_relation<typename CollectionType::value_type::value_type, Type>;
-    // return new relation_type(attr.join_column, attr.inverse_join_column);
+    auto creator = [&join_columns] {
-    // };
+       return std::make_unique<relation_value_type>(join_columns.inverse_join_column, join_columns.join_column);
+    };
+
+    auto node = schema_node::make_relation_node<relation_value_type>(schema_, id, std::move(creator));
+
+    auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, node_);
+    auto join_endpoint = std::make_shared<relation_endpoint>(join_columns.join_column, relation_type::BELONGS_TO, node);
+    auto inverse_join_endpoint = std::make_shared<relation_endpoint>(join_columns.inverse_join_column, relation_type::BELONGS_TO, node);
+    node_->info_->register_relation_endpoint(typeid(CollectionType::value_type::value_type), local_endpoint);
+    node->info_->register_relation_endpoint(node_->type_index(), inverse_join_endpoint);
+    link_relation_endpoints(local_endpoint, inverse_join_endpoint);
+    node->info_->register_relation_endpoint(typeid(CollectionType::value_type::value_type), join_endpoint);
+    result = schema_.attach_node(node, "");
+    if (!result) {
+      // Todo: throw internal error
+      return;
+    }
+  } else {
+    const auto foreign_node = result.value();
+    const auto local_endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_MANY, node_);
+    node_->info_->register_relation_endpoint(typeid(CollectionType::value_type::value_type), local_endpoint);
+    const auto it = foreign_node->info_->find_relation_endpoint(node_->type_index());
+    if (it == foreign_node->info().endpoint_end()) {
+      // Todo: Throw internal error
+      return;
+    }
+    link_relation_endpoints(local_endpoint, it->second);
   }
 }
 
 template<typename Type>
 template<class ForeignPointerType>
-void relation_completer<Type>::on_has_one(const char *id, ForeignPointerType &/*obj*/,
+void relation_completer<Type>::on_has_one(const char *id,
+                                          ForeignPointerType &/*obj*/,
                                           const utils::foreign_attributes &/*attr*/) {
   auto ti = std::type_index(typeid(typename ForeignPointerType::value_type));
-  if (const auto result = schema_.find_node(ti); !result.is_ok() && schema_.expected_node_map_.count(ti) == 0) {
+  if (const auto result = schema_.find_node(ti); !result.is_ok()) {
-    schema_.expected_node_map_.insert({
+      // Node was not found
-      ti, schema_node::make_node<typename ForeignPointerType::value_type>(schema_, ti.name())
+      // Create node without the foreign relation endpoint
-    });
+      log_.debug("node '%s' has foreign key '%s' has one '%s'", node_->name().c_str(), id, ti.name());
+      node_->info_->register_relation_endpoint(ti, std::make_shared<relation_endpoint>(id, relation_type::HAS_ONE, node_));
   } else {
     const auto &foreign_node = result.value();
-    if (const auto rit = foreign_node->info().find_relation_endpoint(ti); rit != foreign_node->info().endpoint_end()) {
+    if (const auto it = foreign_node->info().find_relation_endpoint(typeid(Type)); it != foreign_node->info().endpoint_end()) {
-      if (rit->second->is_has_many()) {
+      if (it->second->is_belongs_to()) {
-      } else if (rit->second->is_has_one()) {
+          it->second->node_ = foreign_node;
+          const auto endpoint = std::make_shared<relation_endpoint>(id, relation_type::HAS_ONE, node_);
+          node_->info_->register_relation_endpoint(ti, endpoint);
+          link_relation_endpoints(endpoint, it->second);
       } else {
+        // Todo: Throw internal error
+        return;
       }
     }
   }
@@ -401,7 +449,8 @@ void relation_completer<Type>::on_has_one(const char *id, ForeignPointerType &/*
 
 template<typename Type>
 template<class ForeignPointerType>
-void relation_completer<Type>::on_belongs_to(const char *id, ForeignPointerType & /*obj*/,
+void relation_completer<Type>::on_belongs_to(const char *id,
+                                             ForeignPointerType & /*obj*/,
                                              const utils::foreign_attributes & /*attr*/) {
   using value_type = typename ForeignPointerType::value_type;
   const auto ti = std::type_index(typeid(value_type));
@@ -416,7 +465,11 @@ void relation_completer<Type>::on_belongs_to(const char *id, ForeignPointerType
     // Check foreign node and relation endpoint
     if (const auto it = foreign_node->info_->find_relation_endpoint(typeid(Type)); it != foreign_node->info().endpoint_end()) {
       // Found corresponding relation endpoint in the foreign node
-      if (it->second->foreign_endpoint()->node().type_index() == typeid(many_to_many_relation<Type, value_type>)) {
+      if (it->second->is_has_one()) {
+          const auto endpoint = std::make_shared<relation_endpoint>(id, relation_type::BELONGS_TO, node_);
+          node_->info_->register_relation_endpoint(ti, endpoint);
+          link_relation_endpoints(endpoint, it->second);
+      } else if (it->second->foreign_endpoint()->node().type_index() == typeid(many_to_many_relation<Type, value_type>)) {
         // Endpoint is a "many_to_many_relation". This means there
         // is a "many_to_many_relation" node attached. Because of being a
         // "belongs_to"-relation the "many_to_many_relation" can be removed
@@ -429,10 +482,9 @@ void relation_completer<Type>::on_belongs_to(const char *id, ForeignPointerType
         // check type
       }
     } else {
-      // Relation node was not found, create endpoint.
+      // Relation node was not found, create only endpoint.
       const auto endpoint = std::make_shared<relation_endpoint>(id, relation_type::BELONGS_TO, node_);
       node_->info_->register_relation_endpoint(ti, endpoint);
-      link_relation_endpoints(endpoint, it->second);
     }
   }
 }

include/matador/orm/session_query_builder.hpp

@@ -8,6 +8,7 @@
 
 #include "matador/sql/connection.hpp"
 
+#include "matador/object/join_columns_collector.hpp"
 #include "matador/object/schema.hpp"
 
 #include "matador/utils/result.hpp"
@@ -18,48 +19,6 @@
 
 namespace matador::orm {
 
-struct join_columns
-{
-  std::string join_column;
-  std::string inverse_join_column;
-};
-
-class join_column_collector
-{
-public:
-  template<class Type>
-  join_columns collect() {
-    join_columns_ = {};
-    Type obj;
-
-    access::process(*this, obj);
-
-    return join_columns_;
-  }
-  template < class V >
-  void on_primary_key(const char * /*id*/, V &, std::enable_if_t<std::is_integral_v<V> && !std::is_same_v<bool, V>>* = nullptr) {}
-  static void on_primary_key(const char * /*id*/, std::string &, size_t) {}
-  static void on_revision(const char * /*id*/, unsigned long long &/*rev*/) {}
-  template<typename Type>
-  static void on_attribute(const char * /*id*/, Type &, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
-  template<class Pointer>
-  static void on_belongs_to(const char * /*id*/, Pointer &obj, const utils::foreign_attributes &attr) {}
-  template<class Pointer>
-  static void on_has_one(const char * /*id*/, Pointer &obj, const utils::foreign_attributes &attr) {}
-  template<class ContainerType>
-  static void on_has_many(ContainerType &, const char *join_column, const utils::foreign_attributes &attr) {}
-  template<class ContainerType>
-  void on_has_many_to_many(const char * /*id*/, ContainerType &/*c*/, const char *join_column, const char *inverse_join_column, const utils::foreign_attributes &/*attr*/) {
-    join_columns_.join_column = join_column;
-    join_columns_.inverse_join_column = inverse_join_column;
-  }
-  template<class ContainerType>
-  static void on_has_many_to_many(const char * /*id*/, ContainerType &/*c*/, const utils::foreign_attributes &/*attr*/) {}
-
-private:
-  join_columns join_columns_;
-};
-
 struct entity_query_data {
   std::shared_ptr<sql::table> root_table;
   std::string pk_column_name{};
@@ -255,7 +214,7 @@ public:
       throw query_builder_exception{query_build_error::MissingPrimaryKey};
     }
 
-    const auto join_columns = join_column_collector_.collect<typename ContainerType::value_type::value_type>();
+    const auto join_columns = join_columns_collector_.collect<typename ContainerType::value_type::value_type>();
 
     append_join(
       sql::column{table_info_stack_.top().table, table_info_stack_.top().info.get().definition().primary_key()->name()},
@@ -288,7 +247,7 @@ private:
   entity_query_data entity_query_data_;
   unsigned int column_index{0};
   unsigned int table_index{0};
-  join_column_collector join_column_collector_;
+  object::join_columns_collector join_columns_collector_;
 };
 
 template<class Pointer>

source/core/object/schema.cpp

@@ -70,10 +70,6 @@ utils::result<std::shared_ptr<attribute_definition>, utils::error> schema::refer
     return utils::ok((*result)->info().reference_column());
   }
 
-  if (const auto it = expected_node_map_.find(type_index); it != expected_node_map_.end()) {
-    return utils::ok(it->second->info().reference_column());
-  }
-
   return utils::failure(result.err());
 }
 
@@ -81,7 +77,12 @@ 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.name() << "::" << it->second->field_name() << " (" << it->second->type_name() << ") <---> " << it->second->foreign_endpoint()->node().name() << "::" << it->second->foreign_endpoint()->field_name() << " (" << it->second->foreign_endpoint()->type_name() << ")\n";
+      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";
+      } else {
+        os << "\n";
+      }
     }
   }
 }
@@ -104,7 +105,7 @@ utils::result<schema::node_ptr, utils::error> schema::attach_node(const std::sha
     parent_node = *result;
   }
 
-  push_back_child(parent_node, node);
+  insert_node(parent_node, node);
 
   // Todo: check return value
   nodes_by_name_.insert({node->name(), node})/*.first*/;
@@ -123,7 +124,7 @@ utils::result<schema::node_ptr, utils::error> schema::attach_node(const std::sha
     return result;
   }
 
-  push_back_child(*result, node);
+  insert_node(*result, node);
 
   // Todo: check return value
   nodes_by_name_.insert({node->name(), node})/*.first*/;
@@ -150,7 +151,7 @@ utils::result<schema::node_ptr, utils::error> schema::find_node(const std::type_
   return utils::ok(i->second);
 }
 
-void schema::push_back_child(const node_ptr &parent, const node_ptr &child) {
+void schema::insert_node(const node_ptr &parent, const node_ptr &child) {
   child->parent_ = parent;
   child->previous_sibling_ = parent->last_child_->previous_sibling_;
   child->next_sibling_ = parent->last_child_;

test/orm/orm/SessionQueryBuilderTest.cpp

@@ -197,8 +197,8 @@ TEST_CASE("Create sql query data for entity with eager many to many", "[query][e
   connection db("noop://noop.db");
   schema scm("noop");
   auto result = scm.attach<recipe>("recipes")
-    .and_then( [&scm] { return scm.attach<ingredient>("ingredients"); } )
+    .and_then( [&scm] { return scm.attach<ingredient>("ingredients"); } );
-    .and_then( [&scm] { return scm.attach<recipe_ingredient>("recipe_ingredients"); } );
+    // .and_then( [&scm] { return scm.attach<recipe_ingredient>("recipe_ingredients"); } );
 
   session_query_builder eqb(scm);
 
@@ -242,8 +242,8 @@ TEST_CASE("Create sql query data for entity with eager many to many (inverse par
   connection db("noop://noop.db");
   schema scm("noop");
   auto result = scm.attach<student>("students")
-    .and_then( [&scm] { return scm.attach<course>("courses"); } )
+    .and_then( [&scm] { return scm.attach<course>("courses"); } );
-    .and_then( [&scm] { return scm.attach<student_course>("student_courses"); } );
+    // .and_then( [&scm] { return scm.attach<student_course>("student_courses"); } );
 
   session_query_builder eqb(scm);