Flutter删除sqlite中的所有行

Question

需要从SQLite中删除所有行

这个文件包含了数据库的所有功能

class DatabaseHelper {
static final _databaseName = "MyDatabase.db";
static final _databaseVersion = 1;
static final table = 'cart_table';
// make this a singleton class
DatabaseHelper._privateConstructor();
static final DatabaseHelper instance = DatabaseHelper._privateConstructor();
// only have a single app-wide reference to the database
static Database _database;
Future<Database> get database async {
if (_database != null) return _database;
// lazily instantiate the db the first time it is accessed
_database = await _initDatabase();
return _database;
}
// this opens the database (and creates it if it doesn't exist)
_initDatabase() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(documentsDirectory.path, _databaseName);
return await openDatabase(path,
version: _databaseVersion,
onCreate: _onCreate);
}
// SQL code to create the database table
Future _onCreate(Database db, int version) async {
await db.execute("CREATE TABLE $table ("
"uId INTEGER PRIMARY KEY,"
"id INTEGER,"
"title TEXT,"
"image TEXT,"
"color TEXT,"
"price TEXT,"
"sizeselect TEXT"
")");

}

Future<int> insert(cart) async {
print(cart.id);
Database db = await instance.database;
return await db.insert(table, cart.toJson());
}
Future<List<Map<String, dynamic>>> queryAllRows() async {
Database db = await instance.database;
return await db.query(table);
}
Future<int> queryRowCount() async {
Database db = await instance.database;
return Sqflite.firstIntValue(await db.rawQuery('SELECT COUNT(*) FROM $table'));
}
Future<int> delete(int id, columnId) async {
print(columnId);
print(id);
Database db = await instance.database;
return await db.delete(table, where: '$columnId = id');
}
deleteAll() async {
Database db = await instance.database;
return await db.rawDelete("Delete * from $table");
}
}

我需要删除所有行。所以我要这样做

final dbHelper = DatabaseHelper.instance;
allRows = await dbHelper.queryAllRows();

显示Unhandled Exception: DatabaseException(near "*": syntax error (code 1 SQLITE_ERROR): , while compiling: Delete * from cart_table) sql 'Delete * from cart_table' args []}

我不明白为什么它显示了一个错误因为不需要传递任何东西，它显示了一个错误。我只需要删除整个表

Answer 1

尝试在没有*的情况下调用删除操作:

delete from cart_table

Answer 2

不需要使用*。只需像下面的代码那样调用

clearUserTable() async {
Database db = await instance.database;
return await db.rawDelete("DELETE FROM $tableName");
}