When you run an online store, it's tempting to list your products on as many stores as possible so that you can get as much revenue as possible. A great example of this gone wrong is when you have a WooCommerce store where you list a kite for $10 and you have an eBay store in which you sell the exact same kite for the same price. If you update one price and forget to update the other, you can run into the following problems:
- You could miss out on additional income.
- Customers could find out they paid a higher price and demand a refund (or, even worse, they refund on one system and rebuy the exact item on your other site).
- You could oversell a product and not have enough stock to fulfill orders.
In general, it's a bad idea to store data in two or more places. You always want to store it in just one place. This principle is called the singular source...