A target database (4) connected to the Internet (NET) is designed to gather entry data (EI) stored in source databases (1, 2, 3) similar in content, which source databases (1, 2, 3) are likewise connected to the Internet (NET). The target database (4) is designed to compare and enter retrieved entry date (EI) into a target memory module (20) of the target database (4), wherein a check is performed, according to the majority principle, as to which of the mutually deviating entry data (EI) are correct. The target database (4) is further designed to notify an administrator of the source data base (1, 2, 3) from which incorrect entry data (EI) were received.