Version Management For Table Data

Hi,

for my application, I need to be able to store past, current and pending versions for each row for some tables for the purpose of auditing and reporting. here is the scenario. the data from one or more tables is displayed on the screen. user makes few changes and submits the changes. the changes will not be updated in database immediately. instead the changes are sent for approval. during the workflow process, the changes need to be stored in pending state and only when the changes are approved, they need to updated to the live data and before updating the live data, old data needs to be stored somewhere for audit trail and reporting. what are the ways in which this can be modelled? should I have three separate tables one to store pending, one to store current and one to store historical version? or should I merge everything into one single table and have a version indicator in it? in this application changes span across multiple tables. in this case how to implement versioning? should each table take care of its own versioning? user can search for pending/current/historical data from the screen by providing various search criteria and the data may come from one or more tables related to each other. Is there a standard approach to deal with this kind of scenario?

Thanks,
RK