In its true sense, data protection is not protecting data but the identity of the individual. As the "data subject" (that's the official term) you have certain rights, which are established in data protection law applicable throughout the EU.
First of all there's the right to informational self determination; in other words, you yourself should be able to determine how your personal data is used.
You can exercise this right when you are briefed by the "processing centre" before your data is processed and you are told the specific purpose for which the data will be processed.
Only then can you protect your other rights: the right to information, the right to correct and if necessary delete or block any of your stored data.