addSql('ALTER TABLE employee ADD short_code VARCHAR(16) DEFAULT NULL'); $this->addSql('CREATE UNIQUE INDEX uniq_employee_shortcode ON employee (short_code)'); } public function down(Schema $schema): void { // this down() migration is auto-generated, please modify it to your needs $this->addSql('DROP INDEX uniq_employee_shortcode ON employee'); $this->addSql('ALTER TABLE employee DROP short_code'); } }