addSql('ALTER TABLE conference ADD slug VARCHAR(255)'); $this->addSql("UPDATE conference SET slug=CONCAT(LOWER(city), '-', year)"); $this->addSql('ALTER TABLE conference ALTER COLUMN slug SET NOT NULL'); } public function down(Schema $schema): void { // this down() migration is auto-generated, please modify it to your needs $this->addSql('CREATE SCHEMA public'); $this->addSql('ALTER TABLE conference DROP slug'); } }