BUSINESS PLUG-IN
B14
Systems Development
McGraw-Hill/Irwin
© The McGraw-Hill Companies, All Rights Reserved
LEARNING OUTCOMES
1. Summarize the activities associated with the
planning phase in the SDLC
2. Summarize the activities associated with the
analysis phase in the SDLC
3. Summarize the activities associated with the
design phase in the SDLC
4. Summarize the activities associated with the
development phase in the SDLC
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LEARNING OUTCOMES
5. Summarize the activities associated with
the testing phase in the SDLC
6. Summarize the activities associated with
the implementation phase in the SDLC
7. Summarize the activities associated with
the maintenance phase in the SDLC
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Introduction
•
Large, complex IT systems take teams of
architects, analysts, developers, testers, and
users many years to create
•
The systems development life cycle is the
foundation for many systems development
methodologies such as RAD and agile
–
Systems development life cycle – the overall
process for developing information systems from
planning and analysis through implementation and
maintenance
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Introduction
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Systems Development Life Cycle PHASE 1: PLANNING
•
Planning phase – involves establishing a
high-level plan of the intended project and
determining project goals
•
Primary planning activities include
1. Identify and select the system for
development
2. Assess project feasibility
3. Develop the project plan
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PLANNING 1: Identify and Select the
System for Development
•
Organizations use different forms of
evaluation criteria to determine which
systems to develop
– Critical success factor (CSF) – a factor that is
critical to an organization’s success
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PLANNING 1: Identify and Select the
System for Development
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PLANNING 2: Assess Project
Feasibility
•
Feasibility study – determines if the proposed
solution is feasible and achievable from a
financial, technical, and organizational
standpoint
•
Different types of feasibility studies
–
–
–
–
–
Economic feasibility study
Operational feasibility study
Technical feasibility study
Schedule feasibility study
Legal and contractual feasibility study
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PLANNING 3: Develop the Project
Plan
•
Developing the project plan is a difficult and
important activity
•
The project plan is the guiding force behind
on-time delivery of a complete and successful
system
•
Continuous updating of the project plan must
be performed during every subsequent phase
during the SDLC
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Systems Development Life Cycle –
PHASE 2: ANALYSIS
•
Analysis phase – involves analyzing enduser business requirements and refining
project goals into defined functions and
operations of the intended system
•
Primary analysis activities include:
1. Gather business requirements
2. Create process diagrams
3. Perform a buy vs. build analysis
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ANALYSIS 1: Gather Business
Requirements
•
Business requirements – the detailed set of
business requests that the system must meet in
order to be successful
•
Different ways to gather business requirements
–
–
–
–
–
Joint application development (JAD) session –
where employees meet to define or review the
business requirements for the system
Interviews
Questionnaires
Observations
Review business documents
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ANALYSIS 1: Gather Business
Requirements
•
The system users review the requirements
definition document and determine if they will
sign-off on the business requirements
–
–
Requirements definition document – contains
the final set of business requirements, prioritized in
order of business importance
Sign-off – the system users’ actual signatures
indicating they approve all of the business
requirements
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ANALYSIS 2: Create Process
Diagrams
•
Process modeling – graphically representing
the processes that capture, manipulate, store,
and distribute information between a system
and its environment
•
Common process modeling diagrams include
–
–
Data flow diagram (DFD) – illustrates the
movement of information between external entities
and the processes and data stores within the
system
Computer-aided software engineering (CASE)
tools –automate systems analysis, design, and
development
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ANALYSIS 2: Create Process
Diagrams
•
Sample data flow diagram
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ANALYSIS 3: Perform a Buy vs.
Build Analysis
•
An organization faces two primary choices
when deciding to develop an information
system
1. Buy the information system from a vendor
– Commercial off-the shelf (COTS) – software
package or solution that is purchased to support
one or more business functions and information
systems
– SCM, CRM, and ERP solutions are typically
COTS
2. Build the information system itself
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ANALYSIS 3: Perform a Buy vs.
Build Analysis
•
Organizations must consider the following
when making a buy vs. build decision:
– Are there any currently available products that
fit the needs?
– Are there features that are not available and
important enough to warrant the expense of inhouse development?
– Can the organization customize or modify an
existing COTS to fit its needs?
– Is there a justification to purchase or develop
based on the acquisition cost?
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ANALYSIS 3: Perform a Buy vs.
Build Analysis
•
Three key factors an organization should
also consider when contemplating the
buy vs. build decision
1. Time to market
2. Availability of corporate resources
3. Corporate core competencies
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Systems Development Life Cycle –
PHASE 3: DESIGN
•
Design phase – involves describing the
desired features and operations of the
system including screen layouts,
business rules, process diagrams,
pseudo code, and other documentation
•
Primary design activities include:
1. Design the IT infrastructure
2. Design system models
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DESIGN 1: Design the IT
Infrastructure
•
Sample IT infrastructure
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DESIGN 2: Design System Models
•
Modeling – the activity of drawing a
graphical representation of a design
•
Different modeling types include:
–
–
–
–
Graphical user interface (GUI)
GUI screen design
Data model
Entity relationship diagram (ERD)
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DESIGN 2: Design System Models
•
Sample entity relationship diagram (ERD)
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Systems Development Life Cycle –
PHASE 4: DEVELOPMENT
•
Development phase – involves taking
all of the detailed design documents
from the design phase and transforming
them into the actual system
•
Primary development activities include:
1. Develop the IT infrastructure
2. Develop the database and programs
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Systems Development Life Cycle –
PHASE 5: TESTING
•
Testing phase – involves bringing all the
project pieces together into a special testing
environment to test for errors, bugs, and
interoperability, in order to verify that the
system meets all the business requirements
defined in the analysis phase
•
Primary testing activities include:
1. Write the test conditions
2. Perform the system testing
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TESTING 1: Write the Test
Conditions
•
Test condition – the detailed steps the system must
perform along with the expected results of each step
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TESTING 2: Perform the System
Testing
•
Different types of testing
–
–
–
–
–
–
Unit testing – tests each unit of code upon
completion
Application (or system) testing – verifies that all
units of code work together
Integration testing – exposes faults in the
integration of software components or units
Backup and recovery testing – tests the ability of
an application to be restarted after failure
Documentation testing – verifies instruction
guides are helpful and accurate
User acceptance testing (UAT) – tests if a system
satisfies its acceptance criteria
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Systems Development Life Cycle –
PHASE 6: IMPLEMENTATION
• Implementation phase – involves placing the
system into production so users can begin to
perform actual business operations with the
system
• Primary implementation activities include:
1. Write detailed user documentation
2. Determine implementation method
3. Provide training for the system users
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IMPLEMENTATION 1: Write Detailed
User Documentation
• System users require user documentation
that highlights how to use the system
• User documentation – highlights how to
use the system
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IMPLEMENTATION 2: Determine
Implementation Method
• Four primary implementation methods
1.
2.
3.
4.
Parallel implementation
Plunge implementation
Pilot implementation
Phased implementation
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IMPLEMENTATION 3: Provide
Training for the System Users
• Organizations must provide training for
system users
• Two most popular types of training
include:
– Online training – runs over the Internet or
off a CD-ROM
– Workshop training – set in a classroomtype environment and led by an instructor
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Systems Development Life Cycle –
PHASE 7: MAINTENANCE
•
Maintenance phase – involves performing
changes, corrections, additions, and upgrades
to ensure the system continues to meet the
business goals
•
Primary maintenance activities include:
1. Build a help desk to support the system users
2. Perform system maintenance
3. Provide an environment to support system changes
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MAINTENANCE 1: Build a Help Desk
to Support the System Users
•
Internal system users have a phone number
for the help desk they call whenever they have
issues or questions about the system
–
•
Help desk – a group of people who respond to
internal system user questions
Providing a help desk is an excellent way to
provide comprehensive support for new
system users
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MAINTENANCE 2: Perform System
Maintenance
•
Maintenance – fixing or enhancing an
information system
•
Different types of maintenance include:
–
–
–
–
Adaptive maintenance
Corrective maintenance
Perfective maintenance
Preventative maintenance
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MAINTENANCE 3: PROVIDE AN
ENVIRONMENT TO SUPPORT
SYSTEM CHANGES
•
An organization must modify its systems to
support the business environment
•
It typically accomplishes this through change
management systems and change control
boards
–
–
Change management system – a collection of
procedures to document a change request and define
the steps necessary to consider the change based on
the expected impact of the change
Change control board (CCB) – responsible for
approving or rejecting all change requests
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CLOSING CASE ONE
Disaster at Denver International Airport
•
DIAs baggage system relied on 300
computers to route bags and 4,000
telecars to carry luggage across 21
miles of track
•
Due to baggage system failures, DIA
delayed its opening for 16 months,
costing taxpayers roughly $1 million per
day, which totaled around $500 million
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CLOSING CASE ONE QUESTIONS
1.
One of the problems with DIA’s baggage system was
inadequate testing. Describe the different types of tests
DIA could have used to help ensure its baggage system’s
success
2.
Evaluate the different implementation approaches. Which
one would have most significantly increased the chances
of the project’s success?
3.
Explain the cost of finding errors. How could more time
spent in the analysis and design phase have saved
Colorado taxpayers hundreds of millions of dollars?
4.
Why could BAE not take an existing IT infrastructure and
simply increase its scale and expect it to work?
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CLOSING CASE TWO
Reducing Ambiguity in Business Requirements
•
The number one reason projects fail is bad
business requirements
•
Business requirements are considered “bad”
because of ambiguity or insufficient
involvement of end users during analysis and
design
•
A requirement is unambiguous if it has the
same interpretation for all parties
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CLOSING CASE TWO QUESTIONS
1.
Why are ambiguous business requirements the
leading cause of system development failures?
2.
Why do the words “and” and “or” tend to lead to
ambiguous requirements?
3.
Research the web and determine other reasons for
“bad” business requirements
4.
What is wrong with the following business
requirement: “The system must support employee
birthdays since every employee always has a birthday
every year”
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