a database system comprises an individual station with berth means for receiving an optically readable information carrier with local information . the system reads the carrier and furthermore receives remotely supplied secondary information . it has a processor for processing both local information and secondary information to produce output information , and a user interface for presenting said output information to a user . in particular , the carrier has a read - only part , and a write part for storage of at least one decryption key . the processor is arranged for decrypting the secondary information using said at least one decryption key .