How to implement a two-level relationship in Laravel 4? - php

Question

I try to get the city name from an entity. I get my entity like this :
$entity = Entity::find(1);
And I would like to get the city name like this :
$entity->addresses->cities->name
But it doesn't work ? I tried multiple ways but impossible to get the city corresponding to the entity.
Here is my model :
Entity :
class Entity extends Eloquent {
/**
* The database table used by the model.
*
* #var string
*/
protected $table = 'entities';
public function addresses ()
{
return $this->hasMany('Address');
}
Address :
class Address extends Eloquent {
/**
* The database table used by the model.
*
* #var string
*/
protected $table = 'addresses';
public $timestamps = false;
public function cities ()
{
return $this->belongsTo('City');
}
public function entities ()
{
return $this->belongsTo('Entity');
}
City :
class City extends Eloquent {
/**
* The database table used by the model.
*
* #var string
*/
protected $table = 'cities';
public function addresses ()
{
return $this->hasMany('City');
}
Do I have to do an intermediate manipulation ? Or do I have to add something in my model ?
I have this error :
Undefined property: Illuminate\Database\Eloquent\Collection::$cities (View: /Applications/MAMP/htdocs/project/app/views/administrator/general.blade.php)
Thank you for your help

Answer 1

In your City model, I believe the addresses() function should return $this->hasMany('Address');
Also, there is some errors in how you are traversing the results of your find query.
Remember one Entity has many addresses, so if you are trying to do $entity->address->city, it has no idea which address you are talking about. You will have to loop through them.
Another thing I like to do is not pluralize all your functions. Just make the ones that will return many things plural. For example, one address will only ever have one city (how can one address belong to multiple cities?) It would be most helpful to change the function name to city() then. One city can have many addresses, so you'd want to have an addresses() function in your City model.
With that in mind, the code that should work for you is...
foreach($entity->addresses as $address) {
echo $address->city->name;
}

Answer 2

Since every entity can have multiple addresses and $entity->addresses() returns a Collection-object, you cant directly get all cities. You have to loop through all addresses and get the corresponding cities.
$cities = array();
foreach( $entity->addresses() as $address ) {
$cities[] = $address->city;
}