Eloquent Model保存在DB中但在代码中找不到

Question

Thanks in advance for any help. I have an Invoice Model which has a one-to-many relationship with the payment model and when I loop through an invoice's payments to add all the $payment->net and subtract it from the $invoice->cost to see the balance that is left. The payment that was just made in the same call doesn't appear in $invoice->payments, it feels like its cached.

Invoice.php

public function payments()
{
    return $this->hasMany('App\Payment');
}

public function net() :float
{
    $payments = $this->payments;

    $net = $this->cost;
    foreach ($payments as $payment) {
        $net += $payment->net;
    }

    return $net;
}

public function balance() :float
{
    return ($this->cost - $this->net());
}

Payment.php

public function invoice()
{
    return $this->belongsTo('App\Invoice');
}

PaymentController.php


    $invoice = Invoice::findOrFail($id);

    // Check ownership
    if(!$this->getCurrentUser()->isSuperuser() && $this->getCurrentUser()->id === $invoice->user_id) {
        throw new ModelNotFoundException();
    }

    $payment = new Payment($request->all());
    $payment->ref = Payment::generateRef($invoice->id, $request->input('type'));

    // Check for overpayment
    if($invoice->balance() < $payment->net) {
        throw new BadInputException('Payment exceeds balance.');
    }

    if($payment = $invoice->payments()->save($payment)) {
        if($invoice->balance() == 0) {
            $invoice->status = Invoice::CLOSED;
            $invoice->save();
        }
    }

    return $payment;

Answer 1

This is not the solution I was looking for but I don't like to expend too much time in little problems like this. I'll try to understand why is the model caching later.

The first time I run $invoice->balance() the value gets cached and the function won't take into consideration the new payment made when evaluating the new balance.

so the next time I ran $invoice->balance() i just manually subtract the new net payment.

 if($invoice->balance() - $payment->net == 0) {
     $invoice->status = Invoice::CLOSED;
     $invoice->save();
 }