It is only possible with a small amount of hand coding. The concept is that you keep track of the inventory in the products table as well as the last date and time that the inventory was updated. Then you store orders in the database as they are made also keeping track of the date and time of the purchase.
You can then update your SQL statement in your catalog to remove items that are out of stock or display the stock available with a nested select statement to remove the number sold from the number available the last time the inventory was updated.
Then you need a small amount of hand code on the shopping cart page to make sure when they update their quantities they don't try to change it to a number greater than what is available.
There is an example of this technique in the PowerStore solution, which includes inventory management as well as many other features. You may want to purchase it as a working example of how to integrate similar functionality into your website if some of my description sounds too complex.
