import 'package:nfc_google_sheet/database/database_helper.dart'; import 'package:nfc_google_sheet/model/student.dart'; class StudentDao { static final StudentDao instance = StudentDao._(); StudentDao._(); Future insert(Student student) async { final db = await DatabaseHelper.instance.db; return await db.insert('student', student.toMap()); } Future getByCardId(String cardId) async { final db = await DatabaseHelper.instance.db; final results = await db.query('student', where: 'cardId = ?', whereArgs: [cardId]); if (results.isEmpty) return null; return Student.fromMap(results.first); } }