Transcript OBJECT ORIENTED SYSTEM ANALYSIS AND DESIGN

OBJECT ORIENTED SYSTEM
ANALYSIS AND DESIGN
COURSE OUTLINE
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The world of the Information Systems Analyst
Approaches to System Development
The Analyst as a Project Manager
Beginning the Analysis: Investigating System
Requirements
• Modeling System Requirements
• The Object-Oriented Approach to
Requirements
• Evaluating Alternatives for Requirements,
Environment, and Implementation
• Moving to Design
• The Object-Oriented Approach to Design: Use
Case Realization
• Designing Databases
• Designing the User Interface
• Designing System Interfaces, Controls and
Security
• Making the System Operational
• Current Trends in System Development
• System Analysis is really more about
understanding a business and its goals and
strategies, defining requirements for
information systems that support those goals
and strategies, and supporting the business.
• The key to successful system development is
thorough systems analysis and design to
understand what the business requires from
the information system.
Definitions
• System Analysis is the process of understanding
and specifying in detail what the information
system should accomplish.
• Systems design is the process of specifying in
detail how the many components of the
information system should be physically
implemented
• System Analyst is a business professional who
uses analysis and design techniques to solve
business problems using information technology.
The analyst as a business problem
solver
• Developing information systems is not about
writing programs but about solving
organizational problems. A system analyst is a
problem solver rather than a programmer.
INFORMATION SYSTEMS
• A System is a collection of interrelated
components that function together to achieve
some outcome.
• An information system is a collection of
interrelated components that collect, process,
store, and provide as output the information
needed to complete a business task.
• A subsystem is a system that is part of a larger
system
• A supersystem is a larger system that contains
other systems
• Functional decomposition is dividing a system
into components based on subsystems that, in
turn, are further divided into subsystems.
• Functional decomposition involves dividing a
system into components
• Components of an information system include
hardware, software, inputs, outputs, data,
people and procedures.
• System boundary is the separation between a
system and its environment that inputs and
outputs must cross.
• A system analyst should define the inputs and
the outputs
• Automation boundary is the separation
between an automated part of a system and
the manual part of the system.
• The automated part is where work is done by
computers and the manual part is where work
is done by people.
TYPES OF INFORMATION SYSTEM
• Transaction processing systems: capture and
record information about the transactions
that affect the organization. Usually these
transactions create credit or debit entries in
accounting ledgers. TPSs are often called
online transaction processing systems
Management information systems
• Systems that take information captured by
transaction processing systems and produce
reports that management needs for planning
and controlling the business. MISs used by
executives often include external data on the
competitive environment-news about
competitors, stock market reports, economic
forecasts, and information from strategic plans
Decision support and knowledge
based systems
• They allow a user to explore the impact of
available options or decisions or to automate
routine decision making.
• Sometimes this process is referred to as
“what if” analysis.
• Some of these systems use expertise captured
as a knowledge base to mimic the way
decisions are made by experts.
• Enterprise applications are highly integrated
systems that support company-wide
operations and data, often combining aspects
of TPSs, MISs, and DSSs/KBSs.
• Communication support systems support
systems that allow employees to
communicate with each other and with
customers and suppliers.
• Office support systems support systems that
help employees create and share documents,
including reports, proposals, and memos.
Required skills of the systems analyst
• There are three types of knowledge and skills
required by systems analyst
– Technical
– Business
– People
Technical knowledge and skills
• The system analyst should understand
– Computers and how they work
– Devices that interact with computers, including
input, storage and output devices
– Communications networks and protocols that
connect computers
– Database and database management systems
– Programming languages
– Operating systems and utilities
• A system analyst needs to know a lot about tools
and techniques for developing systems.
• Tools are software products that are used to
develop analysis and design specifications and
completed system components. Some tools are
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Software Packages such as Microsoft Access etc
Integrated development environments(IDE)
Computer-Aided system engineering (CASE)
Program code generator, testing tools, configuration
management tools, software library management
tools, documentation support tools, project
management tools etc
• Techniques are strategies for completing specific
system development activities.
• Some techniques
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Project planning techniques
Cost/benefit analysis techniques
Interviewing techniques
Requirements modeling techniques
Architectural design techniques
Network configuration techniques
Database design techniques
Business knowledge and skills
• What business functions do organizations
perform?
• How are organizations structured?
• How are organizations managed?
• What type of work goes on in the organization?
• What makes the organization successful
• What are the strategies and plans of the
organization
• What are the traditions and values of the
organization
People Knowledge and skills
• The analyst should understand how people
– Think
– Learn
– React to change
– Communicate
– Work (in a variety of jobs and levels)