Parent, Child, Child of Child in Laravel - laravel

Question

I have three models, Province, City and Job.
Province has the following:
public function cities() {
return $this->hasmany('City');
}
City has the following:
public function province() {
return $this->belongsTo('Province', 'province_id');
}
public function jobs() {
return $this->hasmany('Job');
}
Job has the following:
public function city() {
return $this->belongsTo('City', 'city_id');
}
I am trying to get the total number of jobs in each province and the following doesn't work. Would appreciate if someone could point out what I am doing wrong?
$province->cities->jobs->count()
Thanks!

Answer 1

You have ready-to-use solution in Eloquent, no need for loading everything and adding up count on the collections.
// Province
public function jobs()
{
return $this->hasManyThrough('Job', 'City');
}
then just:
$province->jobs()->count();
It runs simple SELECT count(*) without loading redundant collections.
Additionally, if you need to eager load that count on the collection of provinces, then use this:
public function jobsCount()
{
return $this->jobs()->selectRaw('count(*) as aggregate')->groupBy('province_id');
}
public function getJobsCountAttribute()
{
if ( ! array_key_exists('jobsCount', $this->relations)) $this->load('jobsCount');
return $this->getRelation('jobsCount')->first()->aggregate;
}
With this you can easily get the count for multiple provinces at once (with just 2 queries executed):
$provinces = Province::with('jobsCount')->get();
foreach ($provinces as $province)
{
$province->jobsCount;
}

Answer 2

This is because cities is a Collection you have to loop through each of them to get the jobs number and add them up.
Within controller: Like so;
$job_count = 0;
$province->cities->each(function ($city) use ($job_count){
$job_count += $city->jobs->count();
});
The $job_count would be equal to the total number of jobs within each of it cities.
Please Note: Be sure to eager load your relations data to reduce the amount of queries that are made on your database.
$province = Province::with('cities', 'cities.jobs')...