Laravel Eloquent: eager loading of multiple nested relationships

问题

What laravel says:

$books = App\Book::with('author.contacts')->get();

What I need is something like this

$books = App\Book::with('author[contacts,publishers]')->get();

where we eager load multiple relationships within a relationship.

Is this possible?

回答1:

You can do

 $books = App\Book::with('author.contacts','author.publishers')->get();

回答2:

Laravel documentation on eager loading recommends listing the relationships in an array as follows:

$books = App\Book::with(['author.contacts', 'author.publishers'])->get();

You can have as many relationships as desired. You can also specify which columns should be included for a relationship like this:

//only id, name and email will be returned for author
//id must always be included
$books = App\Book::with(['author: id, name, email', 'author.contacts', 'author.publishers'])->get();

You may also add constrains as follows:

$books = App\Book::with(['author: id, name, email' => function ($query) {
                                          $query->where('title', 'like', '%first%');
                                     }, 'email', 'author.contacts', 'author.publishers'])->get();

来源：https://stackoverflow.com/questions/35490728/laravel-eloquent-eager-loading-of-multiple-nested-relationships