$user = model('user/User');
$data = $user->relation('profile')->find(1);以下无效：$user = model('user/User');
$data = $user->relation(true)->find(1);
// 报错：Invalid argument supplied for foreach() 最佳答案
$user = model('user/User');
$data = $user->relation('profile')->find(1);以下无效：$user = model('user/User');
$data = $user->relation(true)->find(1);
// 报错：Invalid argument supplied for foreach()