It depends.

By default, deleting a service from within its settings does not delete the attached volume and leaves the volume behind as a stray volume on your project canvas, if this is the case, you can deploy a new database of the exact same time, delete its volume and then mount your stray volume to it, but please note that you need to use the username and password from the deleted database.

If the above doesn't apply to you, and you don't have a backup, I'm sorry but there is no way to recover the database.

Ok, I will check that. Thank you!