Problems with delivery

I've got qmail + mysql. I added a host to rcpthosts, and a username to the
mailbox table with a home dir setup correctly. I send a message to
username@host, and it bounces saying this:

<username@host>:
Sorry. Although I'm listed as a best-preference MX or A for that host, it
isn't in my control/locals file, so I don't treat it as local. (#5.4.6)

I thought the point of having MySQL was so I don't have to fill flat text
files with tons of information about the domains I host and accept mail for.
What am I missing?

-ee99ee