Laravel：如何从查询结果中获取模型？

Question

Suppose I have a query that, among other things, returns user id's, this query was built using DB::table()... rather than using the models, so, as a result, I got a collection with arrays for each retrieved row, something like this:

user_id | calculated_data
--------+----------------
      1 |     123
      2 |     111
      3 |     222
    ... |     ...

Supose I store this collection on a $data variable, of course if I do a foreach ($data as $d) { $d->user_id ... } will work.

But I want this query to return something more like what the ORM does, so instead user_id s, return User models so I can do, for example, a $data->user->name

Can this be even done? if so, how?

Answer 1

You can use the hydrate() function, it accepts an array of stdClass objects (or even associative arrays AFAIR) as input and returns a collection of Eloquent Models , so you can do things like this:

$result = DB::table('users')->take(10)->get();
$users = App\User::hydrate($result->all()); 

You can even get a collection of Eloquent Models directly from a RAW query with the fromQuery() function, ie:

$users = App\User::fromQuery('SELECT * FROM users WHERE id > ?', [2])

Update: If in your collection you don't have all the fields to hydrate a model, you can preload all the users you need with one query and modify your collection , ie:

$users = App\User::find($data->pluck('user_id'));
$data->transform(function($item) use($users) {
            $item->user = $users->where('id', $item->user_id)->first()
            return $item;
        }); 

Answer 2

You need to use Eloquent to call value the "ORM way" I did not find anything related to the query builder in relation to ORM.

You could do something like this:

$flights = App\Flight::all(); 

foreach ($flights as $flight) {
    echo $flight->name;
}

And in the ORM way you would get the user like this:

foreach ($flights as $flight) {
    echo $flight->user->name;
}

Of course you would need to setup the correct relations.

Answer 3

// initial query will return collection of objects
$query = DB::table('user_something')
   ->join('users', 'users.id', 'user_something.user_id');

// You could cast it to the model query, by using fromSub.
// Make sure to alias a subquery same as the model's name,
// otherwise it would not be able to parse models data
User::fromSub($query, 'users');

// The most robust way is to get table name from the model
User::fromSub($query, User::make()->getTable());