Since the marketplace extension is no longer supported and the drivers may be outdated, you may build your own jdbc package/extension:
Configuration Field Explanation:
Alternatively, you may download the jdbc connector creator from the marketplace here https://marketplace.thingworx.com/Items/jdbc-connector-extension
Then you may just view the mashup and use it to package your jdbc jar into an extension (which can be later imported into ThingWorx).
Check out the upcoming Expert Session: Understanding ThingWorx Navigate Licensing in Community "Customer Events" section.