c++ - Empty qsqlrelationaltablemodel -

when put model->select(); after relations, model empty, when put before relations, table displays correctly, when edit cell whole row becomes empty , gets "!" on left. no errors.

qsqlrelationaltablemodel *model = new qsqlrelationaltablemodel(this, db1); model->settable("syllabi"); model->seteditstrategy(qsqltablemodel::onfieldchange); model->select(); model->setrelation(3, qsqlrelation("activity_types", "activity_type_id", "activity_type_name")); model->setrelation(0, qsqlrelation("teachers", "teacher_id", "teacher_name")); //model->select(); qdebug() << model->lasterror();  ui->tableview->setmodel(model); ui->tableview->setitemdelegate(new qsqlrelationaldelegate(ui->tableview)); ui->tableview->horizontalheader()->setstretchlastsection(true); ui->tableview->setcolumnhidden(9, true);