1. Systems development life cycle & development methodologies
Asper School of Business
University of Manitoba
Systems Analysis & Design
Instructor: Bob Travica
Systems development life cycle & development methodologies
Updated: September 2014

2. 3510 Systems Analysis & Design * Bob Travica
Outline
Systems development life cycle
System development methodology
Structured methodology
Object-oriented methodology
Objects and Classes
Inheritance
Specialization/Generalization
Polymorphism
3510 Systems Analysis & Design * Bob Travica

3. Systems development life cycle (SDLC)
SDLC: process of planning, building, using, and updating an information system.
Plan
Develop
Use &
Maintain
3510 Systems Analysis & Design * Bob Travica

4. System development methodology
SD Methodology
Guidelines for developing system.
Kind of knowledge.
Two kinds of methodologies
Structured (since 1970s)
Newer ones focused on rapid development
3510 Systems Analysis & Design * Bob Travica

5. Structured methodology (“Waterfall”)
MAINTAIN DURING PRODUCTION PHASE
*Software development, implementation of design in software – not a system implementation in daily work. *
INSTALLATION,
TESTING
Also called “Waterfall” methodology
3510 Systems Analysis & Design * Bob Travica

6. Object oriented methodology - Unified Process
Project
Planning
Analysis
Installation,
Testing
Development activities are
similar to Waterfall but they
are run many times on
system parts added incrementally.
Iteration =
One run of Analysis, Design, Implementation,
Deployment within a UP phase.
A phase has 1 or more iterations.
3510 Systems Analysis & Design * Bob Travica

7. Structured vs. OO Methodology
Object Oriented
(Unified Process)
Use of development activities (Planning, Analysis..)
Each activity covers a whole phase in SDLC
All activities run in each phase, N-times (iterations)
Names of development phases
Planning, Analysis, Design, Implementation, Installation/Testing
Inception, Elaboration,
Construction, Transition
Appropriate to use
When system goals certain, static IT
When system goals less certain, dynamic IT
Modeling technique
Data Flow Diagrams,
Entity-Relationship Diagrams
Diagrams defined by Unified Modeling Language (Use Cases,
Class Diagrams…)
Relation to reality
Predictive
Adaptive
3510 Systems Analysis & Design * Bob Travica

8. 3510 Systems Analysis & Design * Bob Travica
Object – key concept
Object: Software entity with data (attributes) and methods (associated behaviors, or functions).
Object encapsulates data and processes. Object’s data are private, inaccessible directly to other objects.
Examples of objects
Problem domain objects (student, customer)
User interface (buttons, text boxes)
3510 Systems Analysis & Design * Bob Travica

9. 3510 Systems Analysis & Design * Bob Travica
Object examples
Objects are associated and interact via messages –
calls for applying some function on data (e.g., read).
3510 Systems Analysis & Design * Bob Travica

10. 3510 Systems Analysis & Design * Bob Travica
Class
Class: Definition of object properties.
Like a skeleton od database record plus applicable
data functions (write, read, change…).
Objects are instances of a class (e.g., Customer object is an instance of a Customer class).
Name
Attributes
Functions
Object – An instance of class with specified Values of Attributes (specific data)
12005
09/10/2003
16/10/2003
Class
3510 Systems Analysis & Design * Bob Travica

11. Inheritance and Specialization/Generalization
Inheritance: Property of OO systems allowing for attributes and methods to be shared among objects.
Reduces system development costs.
Inheritance enables a special association between classes called Specialization/Generalization
3510 Systems Analysis & Design * Bob Travica

12. Inheritance & Specialization/ Generalization (Cont.)
Specialization: Subclasses inherit attributes and operations of the superclass, plus have some of their own.
Subclasses “specialize”
the superclass.
Generalization
represented by arrows from subclasses to superclass.
Class “generalizes” attributes & methods
of subclasses.
Parent class or
Super-class
Children classes
or Sub-classes
3510 Systems Analysis & Design * Bob Travica

13. Inheritance and Polymorphism
Polymorphism: Ability of subclasses to react differently to the same.
Same message ”Calculate price” triggers methods specific to subclasses.
3510 Systems Analysis & Design * Bob Travica