1. A database management system comprising: a reception unit configured to receive a new data table input to a database; and an insertion unit configured to execute unique constraint determination processing of determining whether each comparison-subject value as each value registered in a target column in the new data table is different from each comparison reference value as each value registered in a target column in a stored data table in the database, and store the new data table in a second database area different from a first database area storing the stored data table in the database when a determination result obtained in the unique constraint determination processing is true.