How to Build a Business Rules Engine

There is no other rule checking in this instance. The column concerned

may be used in other rules, but we do not need to restrict the removal of the

Required Screen Fields validation rule if this happens. All we are doing is

validating the data that goes into the field in question (i.e., ensuring that a

value is populated and that it is an acceptable value).

There is more to deleting rules in more complex rule types, and this is a

topic we shall return to.

This functionality is implemented in the sample application. It does not require

very advanced design or programming skills. Perhaps the only complex item is the

SQL statement that determines which columns of the base table have not yet been

placed in Required Screen Fields rules, or exist in Required ...