ABSTRACT
The product entity structure œows from the structured analysis modeling discussed in Chapter twelve. It is expressed as a hierarchical relationship between everything that is in the system. The very top of the hierarchy is the system itself. The next layer down will consist of some number of major elements in the system. Each of these is further broken down into their components and this pattern continued to the lowest tiers of the system in each branch. When we begin to develop a new and unprecedented system, using the top-down structured approach recommended in this book, the only element of this hierarchy we know is the system that will accomplish the ultimate function, the need. During the early development phases we need to completely dene the product entity structure by some organized means based on what we know the system must do.
