Laravel 中的 With() 方法是什么？

Question

I had refer some online references for understanding what to do with With method in laravel but still not understand. Laravel with(): What this method does?

Here are some codes which I'm not understand, may I know what the a,b,c,d,e,f refer to?

 $example = Test::with('a', 'b', 'c',
            'd', 'e', 'f');

Answer 1

Let's give you a direct example. If you've user table and that user table related to multiple tables right?? and it belongs to multiple tables as well.

Here, I take Four tables.

city

1. id
2. name

User

1. id
2. name
3. city_id

user_profile

1. id
2. user_id
3. address
4. phone

user_documents

1. id
2. user_id
3. document_name
4. type

---

User belongsTo one city,

User has one profile

User has many documents.

Now, In the User model, you can define the relationship as below.

User.php

//User belongs To City
public function city(){
    return $this->belongsTo('App\City','city_id','id')->withDefault();
}


//User hasone profile
public function profile(){
    return $this->hasOne('App\Profile','user_id','id')->withDefault();
}

//User hasmany document
public function documents(){
    return $this->hasMany('App\UserDocument','user_id','id')->withDefault();
}

Now if you want to access this all data in the controller then you can get it by using with()

Controller

App\User::with('city','profile','documents')->get();

you'll get all data in object as

---

User

id

name

• {city data}

• {profile}

• {documents}

---

In addition, You can get multiple model nested relationship as well, Like city belongs to state and if you want to get state data with city then,

User::with('city.state','profile','documents')->get(): 
//define state relationship in city model you'll get state data with the city as well.

You can also add condition in with()

User::with(['document'=>function ($q){
    $q->where('type','pdf');
}]);