ensure proper table creation in session::create_schema including foreign key constraints

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, schema &repo)
+attribute_definition_generator::attribute_definition_generator(std::vector<object::attribute_definition> &columns, const schema &repo)
 : columns_(columns)
 , repo_(repo)
 {}
@@ -23,7 +23,7 @@ utils::result<std::shared_ptr<attribute_definition>, utils::error> attribute_def
 }
 
 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});
+  const_cast<schema&>(repo_).missing_references_.insert({ti, ref_column});
 }
 
 void fk_attribute_generator::on_primary_key(const char *, std::string &, const size_t size)

source/core/utils/error.cpp

@@ -6,7 +6,7 @@
 namespace matador::utils {
 
 std::string error::message() const {
-  return error_message_;
+  return ec_.message();;
 }
 
 std::string error::category() const {