When a database holds details about people, it's likely to include their first name, surname and their date of birth. In addition to this, specialist information is stored depending on the database's intended use.
Organisations use databases for a variety of reasons:
In the case of the Congestion Charge database, if someone hasn't paid the congestion charge, a fine will be issued. The database would play an integral part in automating the process.
Information stored in the other databases listed could be used in similar ways.