What is the relationship between the Job fields in the Project Server 2007 Reporting Database?

The reporting database in Project Server 2007 contains about 7 "User Views" based on Assignment, Resource, Task, and Project. All have fields for Work, OvertimeWork, ActualWork, MaterialWork, BudgetWork, ActualRegularWork. How do all these fields relate to the formula. I cannot find a good resource.

Thanks for any help.