I would like to know more about the dynamic database connector mentioned in the listing of the free version on the Joomla Extension Directory. "There exists also paid version, that adds even more chart types, as well as dynamic database connector to load data in real-time from database or CSV files."

Could someone tell me a bit more about this or please direct me to where I can find more information as the ability to connect to a database is crucial for our project.

Also, is this ability available in all the listed commercial licenses?

You may look to www.artio.net/fusioncharts/editions-license-and-pricing and see what is difference among several paid editions.
These editions also enables to connect to the external database, drill down data and used it for generating flash chart.