diff --git a/include/matador/object/basic_object_info.hpp b/include/matador/object/basic_object_info.hpp
index 9f7deae..5f1a9ee 100644
--- a/include/matador/object/basic_object_info.hpp
+++ b/include/matador/object/basic_object_info.hpp
@@ -28,7 +28,7 @@ public:
   [[nodiscard]] std::string name() const;
   [[nodiscard]] std::shared_ptr<class object> object() const;
   [[nodiscard]] const std::vector<attribute>& attributes() const;
-  [[nodiscard]] const std::vector<restriction>& constraints() const;
+  [[nodiscard]] const std::list<restriction>& constraints() const;
 
   [[nodiscard]] bool has_primary_key() const;
   [[nodiscard]] const utils::identifier& primary_key() const;
diff --git a/include/matador/object/object.hpp b/include/matador/object/object.hpp
index 3575b7a..448384f 100644
--- a/include/matador/object/object.hpp
+++ b/include/matador/object/object.hpp
@@ -35,7 +35,7 @@ public:
 
   [[nodiscard]] bool has_constraints() const;
   [[nodiscard]] size_t constraint_count() const;
-  [[nodiscard]] const std::vector<restriction>& constraints() const;
+  [[nodiscard]] const std::list<restriction>& constraints() const;
 
   friend std::ostream& operator<<(std::ostream& os, const object& obj);
 
@@ -50,7 +50,7 @@ private:
 
   utils::identifier pk_identifier_;
   std::vector<attribute> attributes_;
-  std::vector<restriction> constraints_;
+  std::list<restriction> 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 adf2774..a2b98bd 100644
--- a/include/matador/object/object_generator.hpp
+++ b/include/matador/object/object_generator.hpp
@@ -170,7 +170,7 @@ void object_generator::create_fk_constraint(const std::string& name) const {
         return;
     }
     const auto obj = fk_object<Type>();
-    restriction pk_constraint(*pk_attr);
+    restriction pk_constraint(pk_attr->index());
     pk_constraint.options_ |= utils::constraints::ForeignKey;
     pk_constraint.owner_ = object_;
     pk_constraint.reference_ = obj;
diff --git a/include/matador/object/restriction.hpp b/include/matador/object/restriction.hpp
index b1e2da3..492978b 100644
--- a/include/matador/object/restriction.hpp
+++ b/include/matador/object/restriction.hpp
@@ -17,17 +17,17 @@ class object;
 
 class restriction {
 public:
-  explicit restriction(const class attribute& attr);
+  explicit restriction(size_t attr_index);
 
-  [[nodiscard]] const class attribute& attribute() const;
+  [[nodiscard]] size_t attribute_index() const;
   [[nodiscard]] std::string column_name() const;
+  [[nodiscard]] utils::constraints options() const;
   [[nodiscard]] std::shared_ptr<object> owner() const;
   [[nodiscard]] bool is_primary_key_constraint() const;
   [[nodiscard]] bool is_foreign_key_constraint() const;
   [[nodiscard]] bool is_unique_constraint() const;
   [[nodiscard]] std::string ref_table_name() const;
   [[nodiscard]] std::string ref_column_name() const;
-
   friend std::ostream& operator<<(std::ostream& os, const restriction& c);
 
   [[nodiscard]] std::string type_string() const;
@@ -37,7 +37,7 @@ private:
   friend class object_generator;
   friend class object;
 
-  const class attribute& attr_;
+  const size_t index_;
   std::weak_ptr<object> owner_;
   std::weak_ptr<object> reference_;
   utils::constraints options_{utils::constraints::None};
diff --git a/source/core/object/basic_object_info.cpp b/source/core/object/basic_object_info.cpp
index 54601f8..53d8ca4 100644
--- a/source/core/object/basic_object_info.cpp
+++ b/source/core/object/basic_object_info.cpp
@@ -25,7 +25,7 @@ const std::vector<attribute>& basic_object_info::attributes() const {
   return object_->attributes();
 }
 
-const std::vector<class restriction>& basic_object_info::constraints() const {
+const std::list<restriction>& basic_object_info::constraints() const {
   return object_->constraints();
 }
 
diff --git a/source/core/object/object.cpp b/source/core/object/object.cpp
index e31ba17..2874c2d 100644
--- a/source/core/object/object.cpp
+++ b/source/core/object/object.cpp
@@ -62,7 +62,7 @@ size_t object::constraint_count() const {
   return constraints_.size();
 }
 
-const std::vector<restriction>& object::constraints() const {
+const std::list<restriction>& object::constraints() const {
   return constraints_;
 }
 
diff --git a/source/core/object/object_generator.cpp b/source/core/object/object_generator.cpp
index 737c10f..7e9ebf6 100644
--- a/source/core/object/object_generator.cpp
+++ b/source/core/object/object_generator.cpp
@@ -30,7 +30,7 @@ void object_generator::create_pk_constraint(const std::string &name) const {
   if (pk_attr == std::end(object_->attributes_)) {
     return;
   }
-  restriction pk_constraint(*pk_attr);
+  restriction pk_constraint(pk_attr->index());
   pk_constraint.options_ |= utils::constraints::PrimaryKey;
   pk_constraint.owner_ = object_;
   object_->constraints_.emplace_back(std::move(pk_constraint));
@@ -41,7 +41,7 @@ void object_generator::create_unique_constraint(const std::string &name) const {
   if (pk_attr == std::end(object_->attributes_)) {
     return;
   }
-  restriction pk_constraint(*pk_attr);
+  restriction pk_constraint(pk_attr->index());
   pk_constraint.options_ |= utils::constraints::Unique;
   pk_constraint.owner_ = object_;
 }
diff --git a/source/core/object/restriction.cpp b/source/core/object/restriction.cpp
index 496bb17..f6e4cf8 100644
--- a/source/core/object/restriction.cpp
+++ b/source/core/object/restriction.cpp
@@ -4,16 +4,23 @@
 #include "matador/object/object.hpp"
 
 namespace matador::object {
-restriction::restriction(const class attribute& attr)
-: attr_(attr) {}
+restriction::restriction(const size_t attr_index)
+: index_(attr_index) {}
 
-const class attribute& restriction::attribute() const {
-  return attr_;
+size_t restriction::attribute_index() const {
+  return index_;
 }
 
 std::string restriction::column_name() const {
-  return attr_.name();
+  const auto o = owner_.lock();
+  return o ? o->attributes().at(index_).name() : "";
 }
+
+utils::constraints restriction::options() const {
+  const auto o = owner_.lock();
+  return o ? o->attributes().at(index_).attributes().options() : utils::constraints::None;
+}
+
 std::shared_ptr<object> restriction::owner() const {
   return owner_.lock();
 }
diff --git a/source/orm/query/intermediates/query_alter_table_intermediate.cpp b/source/orm/query/intermediates/query_alter_table_intermediate.cpp
index 677b4f4..23c0dd7 100644
--- a/source/orm/query/intermediates/query_alter_table_intermediate.cpp
+++ b/source/orm/query/intermediates/query_alter_table_intermediate.cpp
@@ -33,7 +33,7 @@ query_add_foreign_key_constraint_intermediate query_add_key_constraint_intermedi
 
 executable_query query_alter_table_intermediate::add_constraint(const object::restriction &rest) {
   context_->parts.push_back(std::make_unique<internal::query_add_constraint_part_by_constraint>(
-    table_constraint{rest.column_name(), rest.owner()->name(), rest.attribute().attributes().options(), rest.ref_table_name(), rest.ref_column_name()}
+    table_constraint{rest.column_name(), rest.owner()->name(), rest.options(), rest.ref_table_name(), rest.ref_column_name()}
   ));
 
   return {context_};
@@ -47,7 +47,7 @@ query_add_key_constraint_intermediate query_alter_table_intermediate::add_constr
 
 executable_query query_alter_table_intermediate::drop_constraint(const object::restriction &rest) {
   context_->parts.push_back(std::make_unique<internal::query_drop_key_constraint_part_by_constraint>(
-    table_constraint{rest.column_name(), rest.owner()->name(), rest.attribute().attributes().options(), rest.ref_table_name(), rest.ref_column_name()})
+    table_constraint{rest.column_name(), rest.owner()->name(), rest.options(), rest.ref_table_name(), rest.ref_column_name()})
   );
   return {context_};
 }
diff --git a/source/orm/query/intermediates/query_create_intermediate.cpp b/source/orm/query/intermediates/query_create_intermediate.cpp
index c0a6f5a..69b11a4 100644
--- a/source/orm/query/intermediates/query_create_intermediate.cpp
+++ b/source/orm/query/intermediates/query_create_intermediate.cpp
@@ -46,11 +46,11 @@ executable_query query_create_table_columns_intermediate::constraints(const std:
   std::list<table_constraint> constraints;
   for (const auto& restr : restrictions) {
     if (restr.is_primary_key_constraint()) {
-      constraints.emplace_back(restr.column_name(), restr.owner()->name(), restr.attribute().attributes().options());
+      constraints.emplace_back(restr.column_name(), restr.owner()->name(), restr.options());
     } else if (restr.is_foreign_key_constraint()) {
-      constraints.emplace_back(restr.column_name(), restr.owner()->name(), restr.attribute().attributes().options(), restr.ref_table_name(), restr.ref_column_name());
+      constraints.emplace_back(restr.column_name(), restr.owner()->name(), restr.options(), restr.ref_table_name(), restr.ref_column_name());
     } else if (restr.is_unique_constraint()) {
-      constraints.emplace_back(restr.column_name(), restr.owner()->name(), restr.attribute().attributes().options());
+      constraints.emplace_back(restr.column_name(), restr.owner()->name(), restr.options());
     }
   }
   context_->parts.push_back(std::make_unique<internal::query_create_table_constraints_part>(constraints));