Using object-oriented analysis and design over traditional structured analysis and design

International Journal of Business Research, March, 2008 by Kenneth Pefkaros

In summary there are three major components of the object-orient analysis and design methodology, and they are as follows:

1. Requirements Modeling: This describes who uses the system and how, consisting of actors, use cases and scenarios. Actors are people or entities that interact with the system. Use cases are defined to describe the expected behavior of the system. Scenarios are particular instances of these use cases that describe a specific requirement of the system.

2. Information Modeling: This describes the entities and relationships in the problem, consisting of objects, their attributes and the particular relationships among one another.

3. Life Cycle Modeling: This describes the way that an object responds to its environment, which is comprised of the various states to which an object can transition, the specific events that invoke these transitions between states and the specific activities that are associated with entering and leaving a particular state (Hoover and Olekshy, 2001).

The following table compares and summarizes these two methodologies (Jadalowen, 2002):

COMPARISON BETWEEN THE TWO METHODOLGIES

Structured System Analysis &      Object Oriented Analysis & Design
Design

SSAD evolved from structured      OOAD evolved from object-
programming.                      oriented programming.

SSAD is process oriented;         OOAD is data oriented;
consequently the processes        consequently data is the
are the primary focus of          primary focus of the system.
the system.

SSAD breaks down the system       OOAD breaks down the system
through the use of data           through the use of Use Cases.
flow diagrams (DFD).

For SSAD the components of the    For OOAD the components of
system are derived from the       system are derived from the
DFD's.                            class diagrams and the
                                  Unified Modeling Language
                                  (UML). (Podeswa, 2005)

For SSAD there are definable      For OOAD there is an
steps: planning, analysis,        iterative and incremental
design, and implementation        approach involving continuous
from start to finish for          testing and refinement of the
the systems development           system from start to finish.
life cycle.

In SASD there is a separation     In OOAD there is encapsu-
of the systems data and           lation of the systems data
processes.                        and processes into objects.

Graphical design and tools are used to analyze and model the system
requirements.

For each methodology there is a step by step process for developing
the system.

Both techniques emphasize the documentation of the system and its
requirements.

5. ADVANTAGES AND DISADVANTAGES OF SSAD

The advantages and disadvantages of the Structured Systems Analysis and Design methodology can be summarized as follows:

5.1 Advantages

* There are distinct milestones for SSAD which makes tracking easier for project management.

* Since SSAD is very visual, it makes it easier for users/programmers to understand.