hasOne with null-able in laravel not working - mysql

Question

I have a customer table which has a field called 'policy_id', where policy_id points to policy table. It is a null-able field, ie. Some customers may not have a policy.
I have a relationship code like this in Customer.php
public function policy() {
return $this->hasOne('App\Models\Policy', "id", "policy_id");
}
But when I issue a search request I am getting error like this:
Illuminate\Database\Eloquent\ModelNotFoundException: No query results for model [App\Models\Policy]
If I modify the function like this:
public function policy() {
if ($this->getAttribute('policy_id')) {
return $this->hasOne('App\Models\Policy', "id", "policy_id");
} else {
return null
}
}
But I am getting an error like this:
Call to a member function getRelationExistenceQuery() on null
Here is my search code:
$c = new Customer();
return Customer::doesntHave('policy')->orWhere(function (Builder $query) use ($req) {
$query->orWhereHas('policy', function (Builder $query) use ($req) {
$p = new Policy();
$query->where($req->only($p->getFillable()))
->orWhereBetween("policy_period_from", [$req->policy_period_start_from, $req->policy_period_start_to])
->orWhereBetween("policy_period_to", [$req->policy_period_end_from, $req->policy_period_end_to])
->orWhereBetween("payment_date", [$req->payment_date_from, $req->payment_date_to]);
});
})->where($req->only($c->getFillable()))->get();
Am I missing something or are there any other ways to do this?
PS: While debugging the above search code is returning successfully, but the exception happening from somewhere inside Laravel after the prepareResponse call.
Thanks in advance.

Answer 1

return $this->hasOne('App\ModelName', 'foreign_key', 'local_key');
Change the order, put the foreign_key policy_id in front of id
In your Customer Model, you need to use belongsTo method:
public function policy() {
return $this->belongsTo('App\Models\Policy', "policy_id", "id");
}
And In your Policy Model, use hasOne:
public function customer() {
return $this->hasOne('App\Models\Customer', "policy_id", "id");
}

Answer 2

First of all, you placed the wrong params.
$this->belongsTo('App\Models\Policy', "FK", "PK");
public function policy() {
return $this->belongsTo('App\Models\Policy','policy_id', 'id');
}
And for null value of policy_id you can use withDefault();
public function policy() {
return $this->belongsTo('App\Models\Policy','policy_id', 'id')->withDefault([
'name' => 'test'
]);;
}

Answer 3

there's a number of problems there but can you perhaps specify the namespace and the class of both your models - Customer and Policy.
By default, the models you create with php artisan make:model will use the \App namespace e.g. \App\Customer and \App\Policy.
Just double check that.
Also, with regards to the relationship, if the Laravel conventions have been followed you could just:
In the Customer model
public function policy() {
return $this->belongsTo(Policy::class);
}
In the Policy model
public function customer() {
return $this->hasOne(Customer::class);
}
of if a multiple customers can be under one policy
public function customers() {
return $this->hasMany(Customer::class);
}
Good luck