Laravel：使用带有 where 子句的 pivot 表获取单个 model

Question

I've got 3 tables:

• Car: belongsToMany Owner
• Owner: belongsToMany Car
• CarOwner: pivot table for Car and Owner with an additional column 'active' that indicates who is the current Owner of a Car

So a Car might have multiple or no Owners and vica versa BUT a Car has only 1 current ('active') Owner.

 class Car extends Model { use HasFactory; public function owners() { return $this->belongsToMany(Owner::class, 'car_owners'); } public function currentOwner() { return $this->owners()->where('active', true)->first(); } }

My problem is if a Car has no active Owner, Laravel throws the following exception when I want to use $car->currentOwner in a Blade template:

App\Models\Car::currentOwner must return a relationship instance, but "null" was returned. Was the "return" keyword used?

How can I handle if a Car doesn't have any active Owners?

Answer 1

You can create a custom attribute instead of a relation function:

    public function getCurrentOwnerAttribute()
    {
        return $this->owners()->where('active', true)->first();
    }