Was having the similar issues as of Ignition version 8.0.3 using MySQL version 5.7-- tables weren’t being created even though the connection was valid and rooted. I could create tables using the DB query browser. Restarting gateway didn’t help.
I was able to resolve the issue by manually adding the Connector/J (I used version 8.0.17) as a custom driver using all the regular options you’d use in the default-provided MySQL Connector/J driver. New connections using this custom driver worked.
I’m not sure if I caused this somehow or if the issue is back as of Ignition 8, but either way, hope this helps someone.