We can specify any of the conflict resolution policies enumerated above for rules having the same security level. However, if there are rules belonging to different security levels, the conflict resolution policy must always favor the dominated rule. This is because delaying
a rule at the dominated level because of the execution of a rule at the dominating level may give rise to a timing channel.
In a multilevel secure active database system we can also specify priorities, but the requirement is that no dominating rule must have a higher priority than a dominated rule. Thus, if priorities are specified by ordering the set of rules, then all rules at dominated levels must be ordered before any rule at the dominating level.
If numeric priorities are to be specified, one approach is to make the priority specification have two parts: one for the security level and the other for the number. For rules having different security levels, the dominated rules will get preference over the dominating rules. For rules having the same security level, the number will decide which rule is chosen for execution.