Databases are everywhere. Every app you use, every website you visit, every transaction you make is backed by a database. But keeping a database running well has always required a lot of human expertise. Expertise for things like tuning performance, managing storage, applying patches, backing up data, scaling up when traffic spikes. For decades, this was just the cost of doing business. You hired database administrators, and they kept the lights on.
A self-driving database is one that handles most of that work itself.