Abstract: A data base system is disclosed in which records are locked out during record changing by using a dynamically generated directed acyclic graph of the records. The edges of the graph, stored in the records themselves, point toward a "root" record representing multiply-shared information. An application to the assignment of telephone facilities to telephone subscribers is also described. A transaction list is maintained to identify locked out records previously locked out during the same transaction.

Abstract: A data base management system is disclosed in which data entities are records representing nodes in an entity-relationship directed graph. The body of each node represents one of the physical entities to be utilized while the edges of each node represent relationships between that physical entity and other physical entities. Some of the edges are hyperedges to permit the identification of simultaneous relationships with more than one other node. An application of this system to the assignment of telephone outside plant equipment to telephone subscribers is also described.