A database consistency method implemented by a database server communicatively coupled to a database storing multiple data records, wherein each of the multiple data records is 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 method comprising: - storing o 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 o 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; - in response to receiving a first request from a first data access system of the data access systems requesting exclusive access to a particular data record for a first time period, o checking the stored associations to determine whether the first data access system is allowed to access the particular data record and, if affirmative, o checking whether exclusive access to the particular data record is still available for the first time period, and, if affirmative, o updating the exclusive access times inventory to grant the first data access system exclusive access to the particular data record for the period of time and exclude all other data access systems from access to the particular data record for the first period of time; the method further comprising: - in response to receiving a second request from a second data access system of the data access systems requesting exclusive access to the particular data record for a second time period including at least a sub-period of the first time period, determining, based on the updated exclusive access times inventory that exclusive access is not available for the second time period and returning a denial notification to the second data access system; characterized in that: the denial notification includes an indication of one or more sub-periods of the second time period in which exclusive access is still available according to the exclusive access times inventory. - storing o 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 o 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; o 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 o 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; - in response to receiving a first request from a first data access system of the data access systems requesting exclusive access to a particular data record for a first time period, o checking the stored associations to determine whether the first data access system is allowed to access the particular data record and, if affirmative, o checking whether exclusive access to the particular data record is still available for the first time period, and, if affirmative, o updating the exclusive access times inventory to grant the first data access system exclusive access to the particular data record for the period of time and exclude all other data access systems from access to the particular data record for the first period of time; o checking the stored associations to determine whether the first data access system is allowed to access the particular data record and, if affirmative, o checking whether exclusive access to the particular data record is still available for the first time period, and, if affirmative, o updating the exclusive access times inventory to grant the first data access system exclusive access to the particular data record for the period of time and exclude all other data access systems from access to the particular data record for the first period of time; - in response to receiving a second request from a second data access system of the data access systems requesting exclusive access to the particular data record for a second time period including at least a sub-period of the first time period, determining, based on the updated exclusive access times inventory that exclusive access is not available for the second time period and returning a denial notification to the second data access system;