My app uses the database data to offer the app user some statistics - the database is updated regularly so I do not want the users to be able to update themselfs the database. Do i have to encrypt the database data or the data communication between the app and the database. I am afraid I have no idea yet what do I have to do exactly so I can protect my database from being updated by the app users
Now I'm confused. What exactly is your requirement?
You make it sound like: "You want to stop your users using your application to update the database?"
Is this correct? If so, then simply
don't allow the users to make changes in your application. No need to muck around with encryption. Set everything to ReadOnly whereever possible (datasets, connections), don't write any commits (and hide the commit option from all DBNavigators).
If your requirement is: "I don't want the users making a change to my database using a different application", then @Groffy has hit the nail on the head. Again, you don't need encryption, just password protect your database
EDIT
Based on your original post I assumed your requirement was "I want to encrypt the database".
Please be very clear in future.