Http request 500 internal server error on Axios put - php

Question

I have an issue submitting my updated data to database.
It accepts all input but when I'm trying to get it saved it gets the error.
This is my route:
Route::resource('Sales', 'SalesController');
How I put my data:
axios.put('/Sales/' + id)
My update method:
public function update(Request $req, $id){
$sales = Sales::find($id);
$sales = new Sales;
$sales->itemQty = $req['itemQty'];
$sales->itemID = $req['itemID'];
$sales->save();
}
My Editing form:
<div class="card-body" v-for="(sale, index) in sales" :key="sale.id">
<form action="/Sales" method="post">
<div>
<input type="hidden" name="_token" :value="csrf">
<div class="form-group">
<div class="form-inline">
<div class="mr-3 mt-2">Item ID: </div>
<input class="form-control mt-2 col" name="itemID[]" maxlength="12" v-model="sale.itemID">
</div>
<div class="form-inline">
<div class="mr-2 mt-2">Quantity: </div>
<input type="number" min="1" class="form-control mt-2 col" placeholder="Quantity" name="itemQty[]" v-model="sale.itemQty">
</div>
</div>
</div>
<div class="updatesale" style="margin:0 auto; text-align: center;">
<button class="btn btn-success mt-2" type="button" name="button" v-on:click="updateSalesRec(sale.id)">Update</button>
</div>
</form>
</div>
What is wrong with it?

Answer 1

You don't need to create another instance of the Sales object after finding it:
public function update(Request $req, $id){
$sales = Sales::find($id);
$sales->itemQty = $req['itemQty'];
$sales->itemID = $req['itemID'];
$sales->save();
}
I don't think your intention is to have your data submitted in array. So remove [] from the input field names:
<div class="card-body" v-for="(sale, index) in sales" :key="sale.id">
<form action="/Sales" method="post">
<div>
<input type="hidden" name="_token" :value="csrf">
<div class="form-group">
<div class="form-inline">
<div class="mr-3 mt-2">Item ID: </div>
<input class="form-control mt-2 col" name="itemID" maxlength="12" v-model="sale.itemID">
</div>
<div class="form-inline">
<div class="mr-2 mt-2">Quantity: </div>
<input type="number" min="1" class="form-control mt-2 col" placeholder="Quantity" name="itemQty" v-model="sale.itemQty">
</div>
</div>
</div>
<div class="updatesale" style="margin:0 auto; text-align: center;">
<button class="btn btn-success mt-2" type="button" name="button" v-on:click="updateSalesRec(sale.id)">Update</button>
</div>
</form>
</div>
Hope this is useful.