How can i make a stop if quantity is not enough? PHP

Question

can anyone teach me how can i make a stop if the quantity is not enough? i'm trying to develop a pos and inventory system using codeigniter framework and here is my portion of code

if($prodid){
    $inputQuantity = (int)$this->input->post('qty')[$x];
    $this->db->where('id', $prodid);
    $this->db->set('qty', "qty-$inputQuantity", false);
    $this->db->update('products');
}

how can i make it stop if the quantity of the products reach 0 and when i process a new transaction with 0 qty of the products it will alert me of not enough stock can anyone help?

Answer 1

You may want check for availabe product stock

// in some model
public function check_stock($productId)
{
   $product = $this->db->get_where($table_name, ['product_id' => $productId])->row();
   
   if(isset($product))
   {
      if($product->stock == 0)
      {
          // There is no more products of this type
          // For example
          die("No more stock");
      }
      else
      {
          // Do other stuff is there is enought stock
          // For example
          // Let the user buy the product
      }
   }
}

I'm assuming you have a products table with stock and product_id columns