PROCESS BUSINESS LOGIC/BUSINESS RULE
DFD
FUNCTIONAL PRIMITIVE
STRUCTURED THEOREM
STRUCTURED PROGRAM
TOP-DOWN PROGRAMMING
MODULAR DESIGN
MODULARISATION
MODULE
PROCESS DESCRIPTION
STRUCTURED ENGLISH
CONTROL STRUCTURE/LOGICAL STRUCTURE
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A process is an activity or fucntion performed for some specific business reason. In general, each proecss performs only one activity.
Every process has a unique identification number,a name, and a description, all of which are noted in the CASE repository. A process defines rules for transforming inputs to outputs. Processess (data transformations) refer to the logical rules that are applied to transform the data into meaningful information. A process receives input data and produces output that has a different content, form, or both. Processes contain the business logic, also called business rules, that transform the data and produce the required results. The process name identifies a specific function and consists of a verb (and an adjective, if necessary) followed by a singular noun.
In DFD, a process symbol can be referred to as a black box (function machine), because the inputs, ouputs, and general functions of the process are known, but the underlying details and logic of the process are hiden. When you create a set of DFDs for a system, you break the processing logic down into smaller units, called functional primitives, that programmers will use to develop code. a functional primitive is a process that consists of a single function that is not exploded further. You document the logic for a functional primitive by writing a process description in the data dictionary.
Later, when the logical design is implemented as a physical system, programmers will transform each functional primitive into program code and modules thta carry out the required steps. A module consists of lines of code (program instructions) that perform a single function. Since each module performs a single specific task, a mainline routine must provide the master control that ties all the modules together and coordinates their activity. this program mainline should show the main processing functions, and theorder in which they are to be performed. It should also show the flow of data and the major control structures. Generally, you should be able to read a pseudocode mainline, and see exactly what is being done in the program. A good way to begin the job of designing a program to solve a particular problem is to identify the major tasks that the program must accomplish. In designing the program, each of these tasks becomes a program module. To help create well-structured program design, each module should consists of a series of properly organized groups of statements known as control structures. A process description (See description of operations) documents the details of a functional primitive, and represents a specific set of processing steps and business logic. Using a set of process description tools, you create a model that is accurate, complete, and concise. Typical processing description tools include structured English, decision tables,and decision trees. When you analyze a functional primitive, you break the processing steps/logic down into smaller units (functional primitives) in a process called modular design. Modular design is based on combinations of three logical structures, sometimes called control structures, which serve as building blocks for the process. Note. Processes are the building blocks of an information system because they represent actual day-to-day business operations (business processes: See operational plans)
Each logical structure must have a single entry and exit point. The three structures are called sequence, selection, and iteration. Structured English is a subset of standard English that describes logical processes clearly and accurately. When you use structured English you must use only the three builing blocks of sequence, selection, and iteration. _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
SEQUENCE
statement a
statement b
statement c
Note. Statement = Instruction = Step = Command = Action
SELECTION
If Blocks
If-Then-EndIf
If-Then-EndIf Structure (single-alternative)
If-Then-Else-EndIf Structure (dual-alternative)
(multiple-alterative)
If-Then-ElseIf-Then-Else-EndIf
If-And-Then-EndIf
If-Or-Then-EndIf
If-Or-And-Then-EndIf
Select Case Blocks
Select Case Of-End Case
Case Of-EndCase
-Relational Operators
-Logical Operators
ITERATION
Repeat-Until (post-test loop)
DoWhile-EndDo
While-End While (pre-test loop)
For-End For (built-in counter-controlled loop)
While-Do-EndWhile
Do-EndDo