Satisfying Multiple Constraints in Real-Time Database Systems

Real-time database systems, such as military command, control and communication, avionics, radar tracking, and managing automated factories, have timing constraints and temporal consistency constraints. The timing constraint requires a transaction to be completed by a specified deadline. The temporal consistency constraints require that data read by a transaction be up-to-date. In such environments, multiple users share the same database, and some of the users may have restricted access to information from the database. Hence, in addition to maintaining timing and temporal consistency constraints, it is also necessary to provide security for real-time databases. Satisfying more than one constraint in a real-time database system is challenging because maintaining one constraint often means the sacrifice of another. For example, in order to meet a deadline, a transaction may have to read some out-of-date data and as a result, may become temporally inconsistent. Similarly, maintenance of ..