Excellent piece, poor title. Curtis Poe writes about the importance of understanding relational databases:

Your application is all about data. For many people in management, they see the app or the web page, but they don’t see the database hidden underneath. They understand that without their data the company is probably in serious trouble, but they don’t give much thought to it. In fact, while total data loss will probably bankrupt your company, few give much thought to the the standard data quality issues that are a constant financial drain because it’s assumed to be part of the cost of doing business. And the developers who don’t understand how to use databases often tell management “that’s just the way this technology works.”

How the Database Will Hurt Your Startup