I would do the following:
- Make sure your JDBC connection string is correct, along with your database credentials.
- If you have the opportunity, try to connect to your MySQL instance from the ThingWorx server directly to make certain the connection is being made, outside of ThingWorx using MySQL Workbench or a local CLI connect if present. If you cannot, search the ThingWorx Application Log and the MySQL log to determine what your connection issue is.
- Enable the Monitoring on the JDBC Thing which can be found on the Configuration Table page.
- After you make changes to the Thing that represents your JDBC connection, use its RestartThing service to force it to re-connect to your MySQL instance.
Upon a successful connection from your JDBC Thing to MySQL, its Property page should list that it is connected and the time at which it last made that connection.
The "null" error I received may have been a combination of typos, choosing the wrong database or table names, or the fact that the user account I employed to connect was not allowed to connect by the MySQL server itself from the IP address of the ThingWorx server. Bby combing through and confirming my settings on the JDBC Thing, I was able to resolve my issue.
I hope these sugestions help you.
