Abstract: Database management system comprises a hierarchical data tree. Each tree node is assigned a unique identifier used as a primary key record in each database table. A root of the tree hierarchy is a system data field created by a service provider. None of the individual subscriptions are assigned to the system data field, but all subscribers can read data from the tree branches located under this root. The data of individual subscriptions serves as branches of a hierarchical data tree. The branches are directly connected to the root data. For each subscription, data access and update policies are set for individual database tables and for individual table records. Each database table that stores shared data has a special data field with flags. The flags define read and modify policies for each. The flags are positions within a bit mask.