One of the problems often encountered is thqt a value might change and that we are only interested to execute the commands immediatelly related to that change. A good solution to this type of problem seemed to be able to be notified of 'data packet' changes. Such a data packet (token) would be an SQL statement that takes input from different places and would place its output into some form of command. When the original data changes this command would be reexecuted. The problem with this at the moment is that it still means that we need to execute all potential queries and that in order to cache the data we get nowhere without comparing the necessary data that goes into the program. So: - the cache needs to know exactly what will go into the program - the notifier needs to execute all queries anyway.