how to solve this error in laravel: ErrorException (E_WARNING) Invalid argument supplied for foreach() - laravel

Question

I am creating a medicine shop invoice system . So at that process, I am creating a invoice form where customer information and invoicing information store in a two different model Customer model and Invoice model.
My invoice form view code below;
<form action="{{url('/invoice')}}" method="post">
{{csrf_field()}}
<div class="form-row">
<div class="col-md-4 col-md-offset-2">
<label for="customerName">Customer Name:</label>
<input type="text" id="customerName" name="customerName" class="form-control"><br>
<label for="address"> Address:</label>
<input type="text" id="address" name="address" class="form-control"><br>
<label for="mobile"> Mobile No.:</label>
<input type="text" id="mobile" name="mobileNumber" class="form-control"><br>
</div>
<div class="col-md-4">
<label for="invoiceNo"> Invoice No.:</label>
<input type="text" id="invoiceNo" name="invoiceNum" class="form-control"><br>
<label for="date"> Date:</label>
<input type="date" id="date" name="date" class="form-control"><br>
</div>
</div>
<hr>
<table class="table table-bordered" cellpadding="10px" cellspacing="5px">
<thead>
<th>Meidicine Name:.</th>
<th>Quantity</th>
<th>Price</th>
<th>Total Price</th>
<th style="text-align: center"><i class="fas fa-plus-square plus "></i></th>
</thead>
<tbody>
<tr>
<td>
<select name="medicineName" id="" class="form-control-sm medicineName" >
#foreach($data as $item)
<option value="{{$item->id}}">{{$item->medicineName}}</option>
#endforeach
</select>
</td>
<td><input type="number" class="form-control-sm quantity" name="quantity"></td>
<td><input type="number" class="form-control-sm price" name="price"></td>
<td><input type="number" class="form-control-sm totalAmount" name="totalAmount"></td>
<td style="text-align: center"><i class="fas fa-times"></i></td>
</tr>
<tr><td><input type="submit" class="btn btn-info btn-sm" value="ADD"></td></tr>
</tbody>
</table>
</form>
In this invoice form medicine name came from another model Medicine using laravel eloquent relationship
my InvoiceController store method code below
public function store(Request $request)
{
$customer = new Customer();
$customer->fill($request->all());
if($customer->save()){
$id = $customer->id;
foreach($request->medicineName as $value => $key) --->error occurs
this line
{
$data = array(
'customer_id' => $id,
'medicine_id' => $value,
'invoiceNum' => $request->invoiceNum[$key],
'date' =>$request->date[$key],
'quantity' =>$request->quantity[$key],
'price' =>$request->price[$key],
'totalAmount'=> $request->totalAmount[$key]
);
Invoice::insert($data);
}
}
return back();
}
when I click ADD button to submit data two different model Customer & Invoice browser can show error look like
"ErrorException (E_WARNING)
Invalid argument supplied for foreach()"
How to solve this type of error, pls anyone can help me..

Answer 1

it's because $request->medicineName is just one element and not an array or collection, try it like this :
public function store(Request $request)
{
$customer = new Customer();
$customer->fill($request->all());
if($customer->save()){
$id = $customer->id;
$data = array(
'customer_id' => $id,
'medicine_id' => $request->medicineName,
'invoiceNum' => $request->invoiceNum,
'date' =>$request->date,
'quantity' =>$request->quantity,
'price' =>$request->price,
'totalAmount'=> $request->totalAmount
);
Invoice::insert($data);
}
return back();
}