diff --git a/include/matador/object/basic_object_info.hpp b/include/matador/object/basic_object_info.hpp
index bd9e948..e088e2d 100644
--- a/include/matador/object/basic_object_info.hpp
+++ b/include/matador/object/basic_object_info.hpp
@@ -6,6 +6,7 @@
 
 #include "matador/utils/identifier.hpp"
 
+#include <list>
 #include <string>
 #include <typeindex>
 
@@ -24,8 +25,7 @@ public:
 
   [[nodiscard]] std::type_index type_index() const;
   [[nodiscard]] std::string name() const;
-  [[nodiscard]] const std::vector<attribute>& attributes() const;
-  // [[nodiscard]] std::shared_ptr<attribute> reference_column() const;
+  [[nodiscard]] const std::list<attribute>& attributes() const;
 
   [[nodiscard]] bool has_primary_key() const;
   [[nodiscard]] const utils::identifier& primary_key() const;
@@ -50,8 +50,6 @@ public:
   [[nodiscard]] bool endpoints_empty() const;
 
 protected:
-  // basic_object_info(std::shared_ptr<repository_node> node, const std::vector<attribute> &attributes, utils::identifier &&pk, const std::shared_ptr<attribute> &pk_as_fk_column);
-  // basic_object_info(std::shared_ptr<repository_node> node, const std::vector<attribute> &attributes);
   basic_object_info(std::shared_ptr<repository_node> node, std::unique_ptr<object> &&obj);
 
 protected:
diff --git a/include/matador/object/constraints_generator.hpp b/include/matador/object/constraints_generator.hpp
index 17b1564..65f4b60 100644
--- a/include/matador/object/constraints_generator.hpp
+++ b/include/matador/object/constraints_generator.hpp
@@ -7,8 +7,8 @@
 #include "matador/utils/field_attributes.hpp"
 #include "matador/utils/primary_key_attribute.hpp"
 
+#include <list>
 #include <typeindex>
-#include <vector>
 
 namespace matador::object {
 class object;
@@ -17,20 +17,20 @@ class repository;
 
 class constraints_generator final {
 private:
-    constraints_generator(std::vector<class constraint> &constraints, const repository &repo, object &obj);
+    constraints_generator(std::list<class constraint> &constraints, const repository &repo, object &obj);
 
 public:
     constraints_generator() = delete;
 
     template < typename Type >
-    static std::vector<class constraint> generate(const repository &repo, object &obj) {
+    static std::list<class constraint> generate(const repository &repo, object &obj) {
         Type t;
         return generate(t, repo, obj);
     }
 
     template < typename Type >
-    static std::vector<class constraint> generate(const Type& t, const repository &repo, object &obj) {
-        std::vector<class constraint> constraints;
+    static std::list<class constraint> generate(const Type& t, const repository &repo, object &obj) {
+        std::list<class constraint> constraints;
         constraints_generator gen(constraints, repo, obj);
         access::process(gen, t);
         return constraints;
@@ -66,10 +66,10 @@ private:
     void create_fk_constraint(const std::type_index& ti, const std::string& name) const;
     void create_unique_constraint(const std::string& name) const;
 
-    [[nodiscard]] std::vector<attribute>::iterator find_attribute_by_name(const std::string &name) const;
+    [[nodiscard]] std::list<attribute>::iterator find_attribute_by_name(const std::string &name) const;
 
 private:
-    std::vector<class constraint> &constraints_;
+    std::list<class constraint> &constraints_;
     const repository &repo_;
     object &obj_;
 };
diff --git a/include/matador/object/object.hpp b/include/matador/object/object.hpp
index a22c93f..441454e 100644
--- a/include/matador/object/object.hpp
+++ b/include/matador/object/object.hpp
@@ -8,6 +8,8 @@
 
 #include "matador/utils/identifier.hpp"
 
+#include <list>
+
 namespace matador::object {
 
 class repository;
@@ -16,22 +18,6 @@ class object {
 public:
   explicit object(std::string name, std::string alias = "");
 
-  // template<typename Type>
-  // static std::unique_ptr<object> generate(const repository& repo, std::string name, std::string alias = "") {
-  //   auto obj = std::make_unique<object>(std::move(name), std::move(alias));
-  //   obj->attributes_ = std::move(attribute_generator::generate<Type>(repo, *obj));
-  //   obj->constraints_ = std::move(constraints_generator::generate<Type>(repo, *obj));
-  //   return obj;
-  // }
-  //
-  // template<typename Type>
-  // static std::unique_ptr<object> generate(const std::unique_ptr<Type>& ptr, const repository& repo, std::string name, std::string alias = "") {
-  //   auto obj = std::make_unique<object>(std::move(name), std::move(alias));
-  //   obj->attributes_ = std::move(attribute_generator::generate(*ptr, repo, *obj));
-  //   obj->constraints_ = std::move(constraints_generator::generate(*ptr, repo, *obj));
-  //   return obj;
-  // }
-
   static const attribute& create_attribute(std::string name, object& obj);
 
   void add_attribute(attribute attr);
@@ -48,11 +34,11 @@ public:
 
   [[nodiscard]] bool has_attributes() const;
   [[nodiscard]] size_t attribute_count() const;
-  [[nodiscard]] const std::vector<attribute>& attributes() const;
+  [[nodiscard]] const std::list<attribute>& attributes() const;
 
   [[nodiscard]] bool has_constraints() const;
   [[nodiscard]] size_t constraint_count() const;
-  [[nodiscard]] const std::vector<class constraint>& constraints() const;
+  [[nodiscard]] const std::list<class constraint>& constraints() const;
 
 private:
   friend class constraints_generator;
@@ -64,8 +50,8 @@ private:
 
   attribute* pk_attribute_{nullptr};
   utils::identifier pk_identifier_;
-  std::vector<attribute> attributes_;
-  std::vector<class constraint> constraints_;
+  std::list<attribute> attributes_;
+  std::list<class constraint> constraints_;
 };
 }
 #endif //MATADOR_OBJECT_HPP
\ No newline at end of file
diff --git a/include/matador/object/object_generator.hpp b/include/matador/object/object_generator.hpp
index f084593..4d5ea1f 100644
--- a/include/matador/object/object_generator.hpp
+++ b/include/matador/object/object_generator.hpp
@@ -86,12 +86,10 @@ public:
     static void on_has_one(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) {}
 
     template <class Pointer>
-    void on_foreign_key(const char *id, Pointer &x) {
+    void on_foreign_key(const char *id, Pointer &/*x*/) {
         const auto type = pk_type_determinator::determine<typename Pointer::value_type>();
         auto &ref = object_->attributes_.emplace_back(id, type, utils::constraints::ForeignKey, null_option_type::NOT_NULL);
         ref.owner_ = object_.get();
-
-        create_fk_constraint(typeid(typename Pointer::value_type), id);
     }
     template<class ContainerType>
     static void on_has_many(const char * /*id*/, ContainerType &, const char *, const utils::foreign_attributes &/*attr*/) {}
@@ -112,7 +110,7 @@ private:
     void create_fk_constraint(const std::type_index& ti, const std::string& name) const;
     void create_unique_constraint(const std::string& name) const;
 
-    [[nodiscard]] std::vector<attribute>::iterator find_attribute_by_name(const std::string &name) const;
+    [[nodiscard]] std::list<attribute>::iterator find_attribute_by_name(const std::string &name) const;
 
     void prepare_primary_key(attribute &ref, utils::identifier &&pk) const;
 
diff --git a/include/matador/orm/session_query_builder.hpp b/include/matador/orm/session_query_builder.hpp
index c1b1258..fd79131 100644
--- a/include/matador/orm/session_query_builder.hpp
+++ b/include/matador/orm/session_query_builder.hpp
@@ -114,27 +114,28 @@ public:
   template<class ContainerType>
   void on_has_many(const char * /*id*/, ContainerType &, const char *join_column, const utils::foreign_attributes &attr) {
     if (attr.fetch() == utils::fetch_type::EAGER) {
-      const auto info = schema_.info<typename ContainerType::value_type::value_type>();
-      if (!info) {
+      const auto result = schema_.basic_info(typeid(typename ContainerType::value_type::value_type));
+      if (!result) {
         throw query_builder_exception{query_build_error::UnknownType};
       }
 
-      auto next = processed_tables_.find(info->get().name());
+      const auto &info = result.value().get();
+      auto next = processed_tables_.find(info.name());
       if (next != processed_tables_.end()) {
         return;
       }
-      table_info_stack_.push({info.value(), std::make_shared<query::table>(info->get().name(), build_alias('t', ++table_index))});
-      next = processed_tables_.insert({info->get().name(), table_info_stack_.top().table}).first;
+      table_info_stack_.push({*result, std::make_shared<query::table>(info.name(), build_alias('t', ++table_index))});
+      next = processed_tables_.insert({info.name(), table_info_stack_.top().table}).first;
       typename ContainerType::value_type::value_type obj;
       access::process(*this , obj);
       table_info_stack_.pop();
 
-      if (!info->get().has_primary_key()) {
+      if (!info.has_primary_key()) {
         throw query_builder_exception{query_build_error::MissingPrimaryKey};
       }
 
       append_join(
-        query::column{table_info_stack_.top().table, table_info_stack_.top().info.get().reference_column()->name()},
+        query::column{table_info_stack_.top().table, table_info_stack_.top().info.get().primary_key_attribute()->name()},
         query::column{next->second, join_column}
       );
     }
@@ -145,12 +146,13 @@ public:
     if (attr.fetch() != utils::fetch_type::EAGER) {
       return;
     }
-    const auto info = schema_.info<typename ContainerType::value_type::value_type>();
-    if (!info) {
+    const auto result = schema_.basic_info(typeid(typename ContainerType::value_type::value_type));
+    if (!result) {
       throw query_builder_exception{query_build_error::UnknownType};
     }
 
-    auto next = processed_tables_.find(info->get().name());
+    const auto &info = result.value().get();
+    auto next = processed_tables_.find(info.name());
     if (next != processed_tables_.end()) {
       return;
     }
@@ -159,23 +161,23 @@ public:
       relation = processed_tables_.insert({id, std::make_shared<query::table>(id, build_alias('t', ++table_index))}).first;
     }
 
-    table_info_stack_.push({info.value(), std::make_shared<query::table>(info->get().name(), build_alias('t', ++table_index))});
-    next = processed_tables_.insert({info->get().name(), table_info_stack_.top().table}).first;
+    table_info_stack_.push({*result, std::make_shared<query::table>(info.name(), build_alias('t', ++table_index))});
+    next = processed_tables_.insert({info.name(), table_info_stack_.top().table}).first;
     typename ContainerType::value_type::value_type obj;
     access::process(*this , obj);
     table_info_stack_.pop();
 
-    if (!info->get().has_primary_key()) {
+    if (!info.has_primary_key()) {
       throw query_builder_exception{query_build_error::MissingPrimaryKey};
     }
 
     append_join(
-      query::column{table_info_stack_.top().table, table_info_stack_.top().info.get().reference_column()->name()},
+      query::column{table_info_stack_.top().table, table_info_stack_.top().info.get().primary_key_attribute()->name()},
       query::column{relation->second, join_column}
     );
     append_join(
       query::column{relation->second, inverse_join_column},
-      query::column{next->second, info->get().reference_column()->name()}
+      query::column{next->second, info.primary_key_attribute()->name()}
     );
   }
 
@@ -184,12 +186,13 @@ public:
     if (attr.fetch() != utils::fetch_type::EAGER) {
       return;
     }
-    const auto info = schema_.info<typename ContainerType::value_type::value_type>();
-    if (!info) {
+    const auto result = schema_.basic_info(typeid(typename ContainerType::value_type::value_type));
+    if (!result) {
       throw query_builder_exception{query_build_error::UnknownType};
     }
 
-    auto next = processed_tables_.find(info->get().name());
+    const auto &info = result.value().get();
+    auto next = processed_tables_.find(info.name());
     if (next != processed_tables_.end()) {
       return;
     }
@@ -198,25 +201,25 @@ public:
     if (relation == processed_tables_.end()) {
       relation = processed_tables_.insert({id, std::make_shared<query::table>(id, build_alias('t', ++table_index))}).first;
     }
-    table_info_stack_.push({info.value(), std::make_shared<query::table>(info->get().name(), build_alias('t', ++table_index))});
-    next = processed_tables_.insert({info->get().name(), table_info_stack_.top().table}).first;
+    table_info_stack_.push({*result, std::make_shared<query::table>(info.name(), build_alias('t', ++table_index))});
+    next = processed_tables_.insert({info.name(), table_info_stack_.top().table}).first;
     typename ContainerType::value_type::value_type obj;
     access::process(*this , obj);
     table_info_stack_.pop();
 
-    if (!info->get().has_primary_key()) {
+    if (!info.has_primary_key()) {
       throw query_builder_exception{query_build_error::MissingPrimaryKey};
     }
 
     const auto join_columns = join_columns_collector_.collect<typename ContainerType::value_type::value_type>();
 
     append_join(
-      query::column{table_info_stack_.top().table, table_info_stack_.top().info.get().reference_column()->name()},
+      query::column{table_info_stack_.top().table, table_info_stack_.top().info.get().primary_key_attribute()->name()},
       query::column{relation->second, join_columns.inverse_join_column}
     );
     append_join(
       query::column{relation->second, join_columns.join_column},
-      query::column{next->second, info->get().reference_column()->name()}
+      query::column{next->second, info.primary_key_attribute()->name()}
     );
   }
 
diff --git a/source/core/object/basic_object_info.cpp b/source/core/object/basic_object_info.cpp
index b16eff7..7e3b132 100644
--- a/source/core/object/basic_object_info.cpp
+++ b/source/core/object/basic_object_info.cpp
@@ -32,14 +32,10 @@ std::string basic_object_info::name() const {
   return node_->name();
 }
 
-const std::vector<attribute>& basic_object_info::attributes() const {
+const std::list<attribute>& basic_object_info::attributes() const {
   return object_->attributes();
 }
 
-// std::shared_ptr<attribute> basic_object_info::reference_column() const {
-  // return pk_as_fk_column_;
-// }
-
 bool basic_object_info::has_primary_key() const {
   return object_->has_primary_key();
 }
diff --git a/source/core/object/constraints_generator.cpp b/source/core/object/constraints_generator.cpp
index 30dca6b..d1df6c2 100644
--- a/source/core/object/constraints_generator.cpp
+++ b/source/core/object/constraints_generator.cpp
@@ -5,7 +5,7 @@
 #include <algorithm>
 
 namespace matador::object {
-constraints_generator::constraints_generator(std::vector<class constraint> &constraints, const repository& repo, object &obj)
+constraints_generator::constraints_generator(std::list<class constraint> &constraints, const repository& repo, object &obj)
 : constraints_(constraints)
 , repo_(repo)
 , obj_(obj) {}
@@ -46,7 +46,7 @@ void constraints_generator::create_unique_constraint(const std::string& name) co
   pk_constraint.owner_ = &obj_;
 }
 
-std::vector<attribute>::iterator constraints_generator::find_attribute_by_name(const std::string& name) const {
+std::list<attribute>::iterator constraints_generator::find_attribute_by_name(const std::string& name) const {
   return std::find_if(std::begin(obj_.attributes_), std::end(obj_.attributes_), [&name](const attribute& elem) {
     return elem.name() == name;
   });
diff --git a/source/core/object/object.cpp b/source/core/object/object.cpp
index 8fe0068..6e1c8d0 100644
--- a/source/core/object/object.cpp
+++ b/source/core/object/object.cpp
@@ -53,7 +53,7 @@ size_t object::attribute_count() const {
   return attributes_.size();
 }
 
-const std::vector<attribute>& object::attributes() const {
+const std::list<attribute>& object::attributes() const {
   return attributes_;
 }
 
@@ -65,7 +65,7 @@ size_t object::constraint_count() const {
   return constraints_.size();
 }
 
-const std::vector<class constraint>& object::constraints() const {
+const std::list<class constraint>& object::constraints() const {
   return constraints_;
 }
 }
\ No newline at end of file
diff --git a/source/core/object/object_generator.cpp b/source/core/object/object_generator.cpp
index eb03170..8b4d0cc 100644
--- a/source/core/object/object_generator.cpp
+++ b/source/core/object/object_generator.cpp
@@ -2,6 +2,8 @@
 
 #include "matador/object/repository.hpp"
 
+#include <algorithm>
+
 namespace matador::object {
 object_generator::object_generator( const repository& repo, std::unique_ptr<object>&& object )
 : repo_(repo)
@@ -47,7 +49,7 @@ void object_generator::create_unique_constraint(const std::string& name) const {
     pk_constraint.owner_ = object_.get();
 }
 
-std::vector<attribute>::iterator object_generator::find_attribute_by_name(const std::string& name) const {
+std::list<attribute>::iterator object_generator::find_attribute_by_name(const std::string& name) const {
     return std::find_if(std::begin(object_->attributes_), std::end(object_->attributes_), [&name](const attribute& elem) {
       return elem.name() == name;
     });
diff --git a/test/core/object/SchemaTest.cpp b/test/core/object/SchemaTest.cpp
index e0b69a7..070e5bc 100644
--- a/test/core/object/SchemaTest.cpp
+++ b/test/core/object/SchemaTest.cpp
@@ -18,13 +18,15 @@ struct student final : person {};
 struct teacher final : person {};
 
 struct names {
-    std::vector<std::string> names_list;
+  unsigned int id{};
+  std::vector<std::string> names_list;
 
-    template<typename Operator>
-    void process(Operator &op) {
-        namespace field = matador::access;
-        field::has_many(op, "name_list", names_list, "names_id", utils::fetch_type::EAGER);
-    }
+  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", utils::fetch_type::EAGER);
+  }
 };
 
 TEST_CASE("Test empty prototype tree", "[schema_node][empty]") {
@@ -75,10 +77,10 @@ TEST_CASE("Test automatic creating of a relation table with foreign key", "[sche
 }
 
 TEST_CASE("Test automatic creating of a relation table with values", "[schema][relation_table][values]") {
-  object::repository tree;
+  object::repository repo;
 
-  REQUIRE( tree.empty() );
+  REQUIRE( repo.empty() );
 
-  auto res = tree.attach<names>("names");
+  auto res = repo.attach<names>("names");
   REQUIRE( res.is_ok() );
 }
\ No newline at end of file