I have a database with the following tables and relationships:
Advert 1-1 Car m-1 Model m-1 Brand
If I want to retrieve an Advert, I can simply use:
Advert::find(1);
If I want the details of the car, I could use:
Advert::find(1)->with('Car');
However, if I also want the detail of the Model (following the relationship with Car), what would the syntax be, the following doesn't work:
Advert::find(1)->with('Car')->with('Model');
Many thanks
It's in the official documentation under "Eager Loading"
Multiple relationships:
$books = Book::with('author', 'publisher')->get();
Nested relationships:
$books = Book::with('author.contacts')->get();
So for you:
Advert::with('Car.Model')->find(1);
Advert::find(1)->with('Car.Model')->get(); will actually return all records for advert in laravel 8. Advert::with('Car.Model')->find(1); returns the specific oneFirst you need to create your relations,
<?php
class Advert extends Eloquent {
public function car()
{
return $this->belongsTo('Car');
}
}
class Car extends Eloquent {
public function model()
{
return $this->belongsTo('Model');
}
}
class Model extends Eloquent {
public function brand()
{
return $this->belongsTo('Brand');
}
public function cars()
{
return $this->hasMany('Car');
}
}
class Brand extends Eloquent {
public function models()
{
return $this->hasMany('Model');
}
}
Then you just have to access this way:
echo Advert::find(1)->car->model->brand->name;
But your table fields shoud be, because Laravel guess them that way:
id (for all tables)
car_id
model_id
brand_id
Or you'll have to specify them in the relationship.
Suppose you have 3 models region,city,hotels and to get all hotels with city and region then
Define relationship in them as follows:-
Hotel.php
class Hotel extends Model {
public function cities(){
return $this->hasMany(City::class);
}
public function city(){
return $this->belongsTo('App\City','city_id');
}
}
City.php
class City extends Model {
public function hotels(){
return $this->hasMany(Hotel::class);
}
public function regions(){
return $this->belongsTo('App\Region','region_id');
}
}
Region.php
class Region extends Model
{
public function cities(){
return $this->hasMany('App\City');
}
public function country(){
return $this->belongsTo('App\Country','country_id');
}
}
HotelController.php
public function getAllHotels(){
// get all hotes with city and region
$hotels = Hotel::with('city.regions')->get()->toArray();
}
will adding the relation function just ask for the relation needed
public function Car()
{
return $this->belongsTo(Car::class, 'car_id')->with('Model');
}
but if you want a nested relation just use the period in the with
Advert::with('Car.Model')->find(1);
but for multi-relation use the array
Advert::with('Car','Model')->find(1);
