<?php
$param = [
  'id' => true, 
  'uid' => true, 
  'product_id' => true, 
  'product_num' => true, 
  'status' => true
];

$data_form = [];
foreach ($param as $key => $value) {
  if($value && !isset($_POST[$key])) {
    $rc = 1;
    return false;
  }else {
    $data_form[$key] = $_POST[$key];
  }
}

$id = $data_form['id'];
unset($data_form['id']);
$res = $wpdb->update('food_cart', $data_form, [
  'id' => $id
]);