Question

get在cursor返回空白

时有效

$excep[] = DB::table('table')->where('user_id', $user)->select('data')->get();
return $excep;  // returns some sql data

但是cursor：

$excep[] = DB::table('table')->where('user_id', $user)->select('data')->cursor();
return $excep; // returns [{}]

信息不足以理解：https://laravel.com/docs/5.5/eloquent#chunking-results

Answer 1

cursor仅可用于迭代，如果您一次需要所有数据，则必须使用get。

// All users will be loaded on memory first on collection and then, iterate.
// You can return all users as return UserModel::get();

foreach (UserModel::get() as $user) {
    $this->sendWellcomeMail($user);
}

// Only one user on memory on each iteration.
// You can NOT return all users with return UserModel::cursor();

foreach (UserModel::cursor() as $user) {
    $this->sendWellcomeMail($user);
}

Laravel游标使用困境

1 个答案: