As a functional programmer, your collections and global caches are off-limits to mutation. But what about your database? If you're still working with mutable table rows, it's time to learn how to make even the stodgiest, legacy-filled relational database functional. In this talk we'll look at why & how to use immutable tables and event-sourced persistence. We'll cover strategies that'll work with your relational database and some straightforward NoSQL solutions that won't require a team of admins.