From the post:
R interface to the MySQL database
Package: RMySQL
Version: 0.8-0Description
The functions in this package allow you interact with one or more MySQL databases from R.
We are not quite to the point where data access is seamless.
So, building a topic map with R out of data stored in MySQL databases require packages such as this one.
The formatting on the post could use from work but otherwise I commend this package to your attention.
BTW, inside-R general community resource site for R, sponsored by Revolution Analytics.