Some plugins and mods store their data in a MySQL database. Under your server → Databases you can create one with a single click – provided your plan includes a database. Haven't booked one yet? Add one under Manage → Book more power → “MySQL database” → “One database”.
You'll then see the host, port, database name, user and password there, along with a ready-made connection string (jdbc:mysql://…) for plugins. Enter these values in the plugin's configuration file and restart the server.
If you need more databases, you can upgrade your plan or get in touch with us.
Note: For security reasons, the database is only reachable from your game server, not from the internet – so accessing it from home with HeidiSQL or similar isn't possible. If you need data from it or a change made, please send us a ticket.