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238 part 3 • the analysis proCess

• Data integrity constraints
• Mathematical and functional derivations
• Logical inferences
• Processing sequences
• Relationships among facts about the business
9. If there is not enough room on the form for a complete structured English description, or if
there is a decision table or tree depicting the logic, include the corresponding table or tree
name.
10. A list of any unresolved issues, incomplete portions of logic, or other concerns. These
issues form the basis of the questions used for follow-up interviews with users or business
experts you have added to your project team.
These items should be entered to complete a process specification form, which includes a pro-
cess number, process name, or both from the data flow diagram, as well as the eight other items
shown in the World’s Trend example (Figure 9.2). Notice that completing this form thoroughly
facilitates linking the process to the data flow diagram and the data dictionary.

Structured English

When process logic involves formulas or iteration, or when structured decisions are not complex,
an appropriate technique for analyzing the decision process is the use of structured English. As
the name implies, structured English is based on (1) structured logic, or instructions organized
into nested and grouped procedures, and (2) simple English statements such as add, multiply, and
move. A word problem can be transformed into structured English by putting the decision rules
into their proper sequence and using the convention of IF-THEN-ELSE statements throughout.

Writing Structured English
To write structured English, you may want to use the following conventions:
1. Express all logic in terms of one of these four types: sequential structures, decision struc-
tures, case structures, or iterations (see Figure 9.3 for examples).
2. Use and capitalize accepted keywords such as IF, THEN, ELSE, DO, DO WHILE, DO
UNTIL, and PERFORM.

Figure 9.3
Structured English Type Example
Examples of logic expressed in
a sequential structure, a decision Sequential Structure Action #1
structure, a case structure, and an A block of instructions in which no Action #2
iteration. branching occurs Action #3
Decision Structure IF Condition A is True
Only IF a condition is true, THEN implement Action A
complete the following ELSE implement Action B
statements; otherwise, jump to the ENDIF
ELSE

Case Structure IF Case #1 Implement Action #1
A special type of decision ELSE IF Case #2
structure in which the cases are Implement Action #2
mutually exclusive (if one occurs, ELSE IF Case #3
the others cannot) Implement Action #3
ELSE IF Case #4
Implement Action #4
ELSE print error
ENDIF

Iteration DO WHILE there are customers.
Blocks of statements that are Action #1
repeated until done ENDDO