use SL::DB::MetaSetup::Order;
 use SL::DB::Manager::Order;
-use SL::DB::Invoice;
 use SL::DB::Helper::FlattenToForm;
 use SL::DB::Helper::LinkedRecords;
 use SL::DB::Helper::PriceTaxCalculator;
 
 __PACKAGE__->meta->initialize;
 
+__PACKAGE__->before_save('_before_save_set_ord_quo_number');
+
+# hooks
+
+sub _before_save_set_ord_quo_number {
+  my ($self) = @_;
+
+  # ordnumber is 'NOT NULL'. Therefore make sure it's always set to at
+  # least an empty string, even if we're saving a quotation.
+  $self->ordnumber('') if !$self->ordnumber;
+
+  my $field = $self->quotation ? 'quonumber' : 'ordnumber';
+  $self->create_trans_number if !$self->$field;
+
+  return 1;
+}
+
 # methods
 
 sub items { goto &orderitems; }
   if ($self->quotation) {
     return [];
   } else {
+    require SL::DB::Invoice;
     return SL::DB::Manager::Invoice->get_all(
       query => [
         ordnumber => $self->ordnumber,