QFC - what does the container do?

Hi! I am using QFC quite some time now but I still did not fully get what the container does. There are: defaults, values, constants, valid and I think I basically got, what they are for (but I am not sure ...) -defaults : values for a new blank form (put there on session start) -values : the values that come back from the user - before processing -constants : the values after processing (checked) -valid : for modal forms shows whether or not a form is filled in correctly already I guess this is very useful if you are working with a multipage-form that has to be filled in completely first and will be written in a database in the very end, when all the data is complete. For me - I am using controller different. I am basically paging through data most of the time with the possibility to enter new data (not often enough that it would make sense to use defaults) So I have forward/backward/jump to data-sets and I never really know whether I should use values or constants to put my data in. Now I usually use constants to put in what I put out to the browser and values for what comes back. But what I would really like to know is: When does the controller do anything on the container array (especially values and constants) Does it do anything at all in these fields? Another question is: When I get my data back I would like to compare constants and values and update the DB in case there is any difference. But there is also a lot of other stuff in values like the buttons and some control-fields (if I would not use CSS to hide them they would be hidden fields :-)) so - there is always a difference and I usually update without effecting data ... Regards Daniel