Data management applications that use multilevel database management system (DBMS) capabilities have the requirement to read and write objects at multiple levels within the bounds of a multilevel transaction. The authors define a new notion of atomicity that is meaningful within the constraints of the multilevel environment. They offer a model of multilevel atomicity that defines varying degrees of atomicity and recognizes that lower security level operations within a transaction must be able to commit or abort independently of higher security level operations. Execution graphs are provided as a tool for analyzing atomicity requirements in conjunction with internal semantic interdependencies among the operations of a transaction and rules for determining the greatest degree of atomicity are proved that can be attained for a given multilevel transaction. Several alternative transaction management algorithms that can be used to preserve multilevel atomicity are presented. >
['Barbara T. Blaustein', 'Sushil Jajodia', 'Catherine D. McCollum', 'LouAnna Notargiacomo']
A model of atomicity for multilevel transactions