修改数据（一）
$user = User::find(1);
$user->name = 'laxe';
$user->save();修改数据（二）返回影响行数
$num = User::where('userId','=',1)->update(['age'=>12]);
var_dump($num);删除数据（一）返回bool
$user = User::find(122);
$user->delete();删除数据（二）通过主键删除返回影响行数
User::destroy(120);
User::destroy(120,119);
User::destroy([118,117]);删除数据（三）通过条件删除
User::where('userid','=','116')->delete();