A database server is communicatively coupled to a database storing multiple data records which are accessible by a number of data access systems communicatively coupled to the database server in order to claim exclusive access to a data record for a specifiable time period by one of the data access systems. The database server stores associations of the data records with the data access systems defining which data access system is generally allowed to access to which data record and an exclusive access times inventory defining which of the data access systems with allowed access has already been granted exclusive access to which data record for which time periods.