SOFTWARE DESIGN METHODS AND REPRESENTATIONS - Software Design for Six-Sigma: A Roadmap for Excellence - page 84

4.3.4 Data-Structure-Oriented Design

Last but not least, this chapter examines data-structure-oriented design. Data-
structure-oriented methods focus on data structure, rather than data-flow-like struc-
tured design methods. 14 Although there are different types of data-structure-oriented
methods, each having a distinct approach and notation, all have some properties in
common. First, each assists in identifying key information objects and operations.
Next, each assumes that the structure of information is hierarchical. Also, each pro-
vides a set of steps for mapping a hierarchical data structure into a program. Some of
the main types of data-structure-oriented design methods are as follows: the Jackson
Development Method, the Warnier-Orr Method, and the Logical Construction of
Programs (LCP) by Warnier. 15
The Jackson Development Method was invented in the 1970s by Michael A.
Jackson and initially was used in an effort to try and make COBOL programming
easier to modify and be reused. 16 However, nowadays the Jackson Development
Method and be applied to all kinds of programming languages. The Jackson Devel-
opment Method includes Jackson Structured Programming as well as Jackson System
Development. 17 These two methods differ from other widely used methods in two
main respects. First, they pay attention initially to the domain of the software and
later to the software itself. Second, they focus on time-ordering that is, they focus on
event sequencing rather than on static data models. Some types of Jackson System
Development programs can be said to be object oriented.
Warnier-Orr diagrams are a kind of hierarchical flowchart that allows for the
organization of data and procedures. Four basic constructs are used on Warnier-Orr
diagrams: hierarchy, sequence, repetition, and alternation. 18 Hierarchy is the most
fundamental of all of the Warnier-Orr constructs. Hierarchy can be defined as a
nested group of sets and subsets as a set of nested brackets where the larger topics
break down into smaller topics, which break down into even smaller topics. Sequence
is the simplest structure to show and includes one level of hierarchy where the
features are listed in the order in which they occur. Repetition is a kind of like a loop
in programming, and happens whenever the same set of data occurs repeatedly or
whenever the same group of actions is to occur repeatedly. Alternation, also known
as selection, is the traditional decision process where a determination can be made to
execute a process, and can be indicated as a relationship between two subsets of a set.
Last but not least is the Logical Construction of Programs, also called the Warnier
Method. It is a variant of Jackson's Structured Programming, and another variant of
this is the Warnier-Orr method. LCP is a data-driven program design technique and
replaces the trial-and-error approach to programming with a disciplined approach,
based on logical rules. 19

14 http://www.mhhe.com/engcs/compsci/pressman/information/olc/AltReqmets.html.
15 http://hebb.cis.uoguelph.ca/

dave/343/Lectures/design.html#1.12.
16 http://en.wikipedia.org/wiki/Jackson Structured Programming.
17 Jackson, Michael, “The Jackson Development Methods.” http://mcs.open.ac.uk/mj665/JSPDDevt.pdf.
18 http://www.davehigginsconsulting.com/pd03.htm.
19 http://www.wayland-informatics.com/T-LCP.htm.

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