Laravel - Eloquent - Get a ralationship without foreign key - php

Question

I'm working on a Laravel project, where i have the models "Reservation" and "Week".
The model "Week" has a starting date and a price, the model "Reservation" has a starting date and an ending date.
I want to be able to do a eloquent selection like this: Reservation::with('weeks')->get(), but if i do something below eloquent doesn't recognize it as a relationship, and i can't use "HasMany" in Reservation model because i don't associate the tables with ids, but only with dates.
How can i get the weeks as a relationship?
class Reservation extends Model
{
public function weeks()
{
return Week::whereDate('starting_date', '>=', $this->starting_date)
->whereDate('starting_date', '<', $this->ending_date)
->orderBy('starting_date')
->get();
}
}
edited: thanks #Tim Lewis

Answer 1

I finally managed it thanks this repository: https://github.com/johnnyfreeman/laravel-custom-relation
The repository is archived and not installable for Laravel 8, so i just copied the files in this folders:
app\Relations\Custom.php
app\Traits\HasCustomRelations.php
This allows me to use Reservation::with('weeks')->get(); with eadger constraints
use App\Models\Week;
use App\Traits\HasCustomRelations;
class Reservation extends Model
{
use HasCustomRelations;
public function weeks()
{
return $this->custom(
Week::class,
// add constraints
function ($relation) {
if($this->starting_date && $this->ending_date) {
$relation->getQuery()
->where('weeks.starting_date', '>=', $this->starting_date)
->where('weeks.starting_date', '<', $this->ending_date);
}
else {
$relation->getQuery();
}
},
// add eager constraints
function ($relation, $models) {
$starting_date = $models[0]->starting_date;
$ending_date = $models[count($models)-1]->ending_date;
$relation->getQuery()
->where('weeks.starting_date', '>=', $starting_date)
->where('weeks.starting_date', '<', $ending_date);
},
// add eager matcher
function ($models, $results, $foreignTable, $relation) {
foreach ($models as $model) {
$model->setRelation($foreignTable, $results
->where('starting_date', '>=', $model->starting_date)
->where('starting_date', '<', $model->ending_date));
}
return $models;
}
);
}
}

Answer 2

You're almost there. Just use an accessor to get the weeks:
public function getWeeksAttribute()
{
return Week::whereDate('starting_date', '>=', $this->starting_date)
->whereDate('starting_date', '<', $this->ending_date)
->orderBy('starting_date')
->get();
}
and you'll be able to get the weeks as if it were any other attribute. If you need to serialize your model to Json, remember to add weeks to the $appends array in your model.