Hi
My answer is not an answer to your problem but maybe can help you somehow.
We transferred a product from Java to dart and the database is MySql.
We faced a lot of problems with the Dart and MySql driver,
the current (Mysql/Dart) tools and drivers are not mature enough.
Then we left our server in Java / servelts, and Dart UI talks to the server over JSON
Our next server version may be Dart/Postgres or Go/MySql, we will neglect Java.
My advice for you is always to choose the right tool or language that fits your needs,
and not based on the team size, otherwise you can end up with more problems,
based on miss fit of the tool to the task.
Shlomo.