用于获取用户列表的Laravel表关系

Question

I'm working on a laravel 5 application. I have 3 tables:

table A: 'users' 

id   |    name
————————————————
1    |    Dave
2    |    Robet
3    |    Jimmy
4    |    Daniel

and Table B classroom_users

user_id | classroom_id 
1       | 5            
4       | 5            
3       | 6  
4       | 5          

I need to return all users 'name' for classroom 5

Please let me know what is the best way to do that. Trough model or Database join

Any help appreciated.

Answer 1

Assuming you have models and its relationships will be defined as below:

Classroom Model:

public function users(){
    return $this->belongsToMany(User::class,'classroom_users','classroom_id','user_id');
}

User Model:

public function classrooms(){
    return $this->belongsToMany(UserClassrooms::class,'classroom_users','user_id','classroom_id');
}

Now, in controller you can retrieve the users belonging to the classroom id 5 as below:

$classroom_id = 5 ;//change this to the id you want
$users = Classroom::find($classroom_id)->users()->get();