title: How to deduct quantity of items in database?
body: <p>I'm creating a system where I must deduct and add by one if the item is borrowed/returned. In my system I have 2 tables: </p>
  
  <pre><code>tblItems(_itemnumber_, _itemname_, _quantity_) 
  tblBorrow(_dateborrowed_, _datedue_, _status_)
  </code></pre>
  
  <p>Where if I borrowed an item the status will be <em>borrowed</em> and the <em>quantity</em> will deducted by 1 and if the status is <em>returned</em> the quantity will added by 1. This is my idea(I already how to add and update) but i don`t know how to code this idea. I'd really appreciate your help.</p>
  
  <p>I`m using imports system.data.oledb</p>