client side of javafx with an existing database

after reading about the topic, I couldn't figure out the best way to approach this issue.
assume a client already have a database, this database can be oracle XE, MySql or Sqlite (I can install any of these on the client PC)
And the javaFx application (developed on a different PC, to be deployed and install later on the client PC) is a simple app, that take a Json or XML file, parse it and insert the data into the database. The table names are fixed and the table rows are known, so that's not the dynamic part. I just want the app to be able to connect to client database.
I know I can deploy an app with Sqlite already in it. but the problem with that approach, is that the client won't have a separate and independent database.
So the question is: how to make a javafx application, that can be configured to connect to the client database ?