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CT026-1 Systems Analysis and Design Overview of current methodologies Slide 2 (of 43)
Topic & structure of the lesson
Overview of current methodologies and their suitability for application domains SSADM Object-oriented RAD
CT026-1 Systems Analysis and Design Overview of current methodologies
Methodologies
Software development methodology structured method based on life cycle model
Why do we need a methodology?
CT026-1 Systems Analysis and Design Overview of current methodologies
Methodologies
Different methodologies Process oriented methodologies
STRADIS (Gane and Sarson)
YSM (Yourdan)
Blended methodologies SSADM
Information Engineering
CT026-1 Systems Analysis and Design Overview of current methodologies
Methodologies
Different methodologies OO methodologies
OO Analysis
Rational Unified Process (RUP)
Rapid development methodologies
People-oriented methodologies
Organizational methodologies
CT026-1 Systems Analysis and Design Overview of current methodologies
Structured Systems Analysis and Design (SSADM)
A “baseline” for comparison and evaluation of other methodologies and for themes in systems development
The true successor to the traditional SDLC approach with new techniques and tools developed since the 1970s
CT026-1 Systems Analysis and Design Overview of current methodologies
Structured Systems Analysis and Design (SSADM)
supported by CASE tools clearly defined deliverables quality checkpointsWaterfall can be classified as this kind of
methodology. vulnerable to any business changes that
happen while the development is still on the way, as it is extremely difficult to go backwards
CT026-1 Systems Analysis and Design Overview of current methodologies
SSADM
forces the developers to well identify and understand system requirements long time before the implementation phase begins.
lack of ability to go backwards makes it unaccommodating to changes as the project proceeds.
system being built can not be presented until it is completely done at the end of the implementation phase.
CT026-1 Systems Analysis and Design Overview of current methodologies
SSADM
Major tools Logical Data Modeling
Logical Data Structure ER Model - Entities & Relationships Documentation
Data Flow Modeling Data Flow Diagrams Documentation
Entity / Event Modelling Entity Life History Documentation
CT026-1 Systems Analysis and Design Overview of current methodologies
SSADM
Version 4 in 1990 has 7 stages1. Feasibility
2. Investigation of current environment
3. Business system options
4. Requirements Specifications
5. Technical system options
6. Logical design
7. Physical design
CT026-1 Systems Analysis and Design Overview of current methodologies
Object Oriented Analysis & Design (OOAD)
different approaches and methodologies Booch Coad and Yourdon Martin and Odell Rumbaugh et al
CT026-1 Systems Analysis and Design Overview of current methodologies
OOAD
OO life cycle analysis design implementation
Deliverables diagrams repository description
CT026-1 Systems Analysis and Design Overview of current methodologies
OOAD
uses a tool called UML (Unified Modeling Language), which is a set of standard in diagramming and modeling techniques invented by three OO champions, Grady Booch, Ivar Jacobson, and James Rumbaugh
CT026-1 Systems Analysis and Design Overview of current methodologies
Comparison between SSADM and OOA
blend of data and process models used
programming code separate from data
maybe waterfallprocess modelexplicitly shows data
flowsshows data store
objects used
code and data bundled in an object
incremental and iterativeuse case implies data flowhas no equivalent to data
store
Structured OO
CT026-1 Systems Analysis and Design Overview of current methodologies
Similarities
show functions required by user may be leveled according to detail strongly related to how information is storedshow external agents interacting with the systempartition functionalities into small partsindicate how data may be storedrefer to attributes
CT026-1 Systems Analysis and Design Overview of current methodologies
Rapid Application Development (RAD)
Introduced code generators and the visual fourth-generation (4G) programming languages such as Microsoft Visual Basic and Borland Delphi
Iterative model allowing back tracking “Working model is worth a thousand pictures” High level of user involvement
CT026-1 Systems Analysis and Design Overview of current methodologies
Phases in RAD
1. Requirements Planning phase
2. User design phase
3. Construction phase
4. Cutover phase
Compared with traditional methods, the entire process is compressed. As a result, the new system is built, delivered, and placed in operation much sooner.
CT026-1 Systems Analysis and Design Overview of current methodologies
RAD
Some part of the system (the core functioning) is developed quickly to be delivered to the users
However as the system can be delivered quickly, users tend to change their expectations of what the system can do, thus the requirements tend to change and expand.
CT026-1 Systems Analysis and Design Overview of current methodologies Slide 40 (of 43)
Follow Up Assignment
List and explain the differences between SSADM and Object-oriented in terms of the activities and phases involved.
CT026-1 Systems Analysis and Design Overview of current methodologies Slide 41 (of 43)
Summary of Main Teaching Points
Overview of current methodologies and their suitability for application domains SSADM Object-oriented RAD
CT026-1 Systems Analysis and Design Overview of current methodologies Slide 42 (of 43)
Question and Answer Session
Q & A