How to Build a Business Rules Engine

When Should Code Be Generated?

All of the basic components to generate code are now in place. It remains to link the

generation of the code to the updating of the of the rule definitions in the screen for

the rule type Required Screen Fields shown in Figure 15.4.

Code generation actually does not have to happen every time this screen is

viewed. It only needs to be done if the definition of a business rule has changed since

the code for the corresponding business process step was last generated. There needs

to be some metadata to do this, and Figure 15.5 shows a reasonable design approach.

In Figure 15.5, the Business Rule table has a column Business Rule Last Updated Date-

time (BRULE_UPD_D) that is updated every time the user updates the definition