db->table_exists('technician_equipment_documents')&&!$this->db->field_exists('installation_location','technician_equipment_documents')){$this->load->dbforge();$this->dbforge->add_column('technician_equipment_documents',array('installation_location'=>array('type'=>'VARCHAR','constraint'=>255,'null'=>true,'after'=>'work_order_no')));}} public function down(){throw new RuntimeException('Lokasi pemasangan dipertahankan untuk audit.');} }