What if you need to access another database?

So, I created a database driven website. After some operating time, the site owners wanted to be able to have others comment on the output.

The database is holding information about widgets and then the site's review of the widgets. Owners want other people to be able to add reviews and comments of their own on the "pretty output" pulling the widget data and comments. (I supposed this is kind of like amazon.com's set-up).

I thought that it would be great to use Word Press to simplify adding comments and tags. - I suppose I could have just coded all of that stuff (hmmm.)

I installed wordpress. The first thing necessary was to get the plugin, Exec-PhP, that allows posts to contain php. That way, posts and pages could call the functions and data already written for the previous site.

However, once I made this work, I couldn't figure out how to get each widget review in the original mysql database to show up as a 'post' in the wordpress database.