Gather the available documentation. Determine counting scope and boundary and identify Functional User Requirements. Measure data functions. Measure transactional functions. Calculate the functional size. Document and report.
The data functions relate to the logical data stored and available for update and retrieval. The transactional functions-external inputs (EIs), external outputs (EOs), and external inquiries (EQs)—perform the processes of storing, updating, retrieving, and displaying the logical data. The specific rules and guidelines for EIs, EOs, and EQs are discussed in this chapter, but remember the concept of an elementary process (EP) as presented in Chapter 5, because a transaction must be confirmed to be an EP before it can be classified as an EI, EO, or EQ.