An Informal Example
As an example of design decisions as mapping functions, let's look at the transition between an analysis model and a design model. Assume that the analysis model contains the elements Bank, Customer, Account, and Transfer, as described on page 49.
Now let's transform this model to a design model. One observation we can make immediately is that some information from the application has to outlive the lifetime of the software system, while others do not. Happily, Enterprise Java Beans (EJBs) provide two forms of beans that correspond to these two needs. An entity bean is a remotely accessible object that can live for the lifetime of the software system and whose state is stored in and loaded from an underlying database. A
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