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PHASE 4SYSTEMS IMPLEMENTATION
Application Development
SYSTEMS ANALYSIS & DESIGN
PHASE 42
SYSTEMS ANALYSIS & DESIGN 3E
SDLC Phases
Phase 4: Systems ImplementationObjectives
Learn about application development, including designing, writing, testing, and documenting programs and code modules
Perform installation and evaluation tasks, including user training, file conversion, system changeover, and evaluation of the results
PHASE 43
SYSTEMS ANALYSIS & DESIGN 3E
Chapter 10
Application Development
PHASE 44
SYSTEMS ANALYSIS & DESIGN 3E
Objectives
Describe the major tasks and activitiesthat are completed during the systems implementation phase
Discuss the role of the systems analyst during application development
Explain the importance of quality assurance and the role of software engineering in software development
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SYSTEMS ANALYSIS & DESIGN 3E
Objectives
Describe the different types of documentation the systems analyst must prepare
Explain the different phases of testing including unit testing, link testing, and system testing
Describe top-down design and modular design and the advantages of these approaches
PHASE 46
SYSTEMS ANALYSIS & DESIGN 3E
Introduction
During the systems implementation phase, the development team uses the system design specification as a blueprint for constructing the new system
Analysts and programmers have different roles during application development
An analyst's main task is to deliver clear, accurate specifications to a programmer
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SYSTEMS ANALYSIS & DESIGN 3E
Quality Assurance
Quality assurance is vitally important in all business areas, including IS functions
The main objective of quality assurance is to detect and avoid problems as early as possible
Quality assurance can detect Inaccurate requirements Design or coding errors Faulty documentation Ineffective testing
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SYSTEMS ANALYSIS & DESIGN 3E
Quality Assurance
Software engineering Stresses quality in software design
Solid design Effective structure Accurate documentation Careful testing
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SYSTEMS ANALYSIS & DESIGN 3E
Quality Assurance Software engineering
Stresses quality in software design Solid design Effective structure Accurate documentation Careful testing
Software Engineering Institute (SEI) Mission is to improve quality of software-
based systems Capability Maturity Model is designed to
improve quality, reduce development time, and cut costs
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Click to see Figure 10-2aClick to see Figure 10-2a Package
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Planning the overall design strategy Use top-down (modular) approach and partition
the system into subsystems and modules
Develop programs and modules Design, code, test, and document
Test the system Link test System test Complete all documentation
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Documentation review and application design Program designs are based on
System design specification Prior phase documentation DFDs Process descriptions Screen layouts Report layouts Source documents Data dictionary entries
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Documentation review and application design Structure (hierarchy) charts
Show the organization of program modules and the functions they perform
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Documentation review and application design Structure (hierarchy) charts
Show the organization of program modules and the functions they perform
Program flowcharts Show the internal logic needed to perform
program tasks and provide output
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Documentation review and application design Structure (hierarchy) charts
Show the organization of program modules and the functions they perform
Program flowcharts Show the internal logic needed to perform
program tasks and provide output Pseudocode
Documents the program’s logical steps
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Coding Process of turning program logic into specific
instructions that can be executed by the computer system
Many programming languages exist Visual C++ Access Basic Visual Basic SQL HTML Java
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Testing the application Testing is necessary to ensure that all programs
function correctly First step is to detect syntax errors and obtain a
clean compilation Next step is to eliminate logic errors
Techniques include desk checking, structured walkthrough, and code review
Final step is testing Unit, link, and systems testing
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Testing the application Unit testing
Involves an individual program Objective is to identify and eliminate
execution errors and any remaining logic errors
Stub testing is a technique of using stubs to represent entry or exit points that will be linked later to another program or data file
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development
Testing the application Link testing
Involves two or more programs that depend on each other
Also called string testing, series testing, or integration testing
Link testing ensures that the job streams are correct
Test data is necessary to simulate actual conditions and test the interface between programs
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SYSTEMS ANALYSIS & DESIGN 3E
Application Development Testing the application
System testing Involves the entire information system and
includes all typical processing situations Requires users to verify all processing
options and outputs Uses live data Involves a final test of all programs Ensures that proper documentation is ready Verifies that all system components work
correctly Confirms that the system can handle
predicted data volumes in a timely and efficient manner
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SYSTEMS ANALYSIS & DESIGN 3E
TRADEOFF How far should you go with system testing? Tradeoff: pressure for the new system from
users and managers vs. the need to avoid major errors
Typical issues to consider What is the judgment of analysts, programmers,
IS management, and the project manager? Do potential problems exist that might affect the
integrity or accuracy of data? Can minor changes be treated as future
maintenance items?
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SYSTEMS ANALYSIS & DESIGN 3E
A KEY QUESTION
During the first two weeks of system testing, a number of minor problems were detected and fixed
One department manager insists on a “no-risk” guarantee, while other users are clamoring for the new system to become operational
How do you respond?
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SYSTEMS ANALYSIS & DESIGN 3E
Documentation
Explains the system and helps peopleinteract with it
Types of documentation Program documentation System documentation Operations documentation User documentation
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SYSTEMS ANALYSIS & DESIGN 3E
Documentation
Program documentation Begins in the systems analysis phase and
continues during systems implementation Includes process descriptions and report layouts Programmers provide documentation with
comments that make it easier to understand and maintain the program
An analyst must verify that program documentation is accurate and complete
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SYSTEMS ANALYSIS & DESIGN 3E
Documentation
System documentation System documentation describes the system’s
functions and how they are implemented Most system documentation is prepared during
the systems analysis and systems design phases Documentation consists of
Data dictionary entries Data flow diagrams Screen layouts Source documents Initial systems request
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SYSTEMS ANALYSIS & DESIGN 3E
Documentation
Operations documentation Typically used in a minicomputer or mainframe
environment with centralized processing and batch job scheduling
Documentation tells the IS operations group how and when to run programs
Common example is a program run sheet, which contains information needed for processing and distributing output
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SYSTEMS ANALYSIS & DESIGN 3E
Documentation User documentation
Typically includes the following items System overview Source document description, with samples Menu and data entry screens Reports that are available, with samples Security and audit trail information Responsibility for input, output, processing Procedures for handling changes/problems Examples of exceptions and error situations Frequently asked questions (FAQ) Explanation of Help & updating the manual
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SYSTEMS ANALYSIS & DESIGN 3E
Documentation
User documentation Written documentation material often is
provided in a user manual Analysts prepare the material and users review it
and participate in developing the manual
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Documentation User documentation
Written documentation material often is provided in a user manual
Analysts prepare the material and users review it and participate in developing the manual
Online documentation can empower users and reduce the need for direct IS support Context-sensitive Help Interactive tutorials Hints and tips Hypertext On-screen demos
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SYSTEMS ANALYSIS & DESIGN 3E
Management Approval
After system testing is complete, the results are presented to management Test results Status of all required documentation Input from users who participated Detailed time schedules, cost estimates, and
staffing requirements
If approved, a schedule for system installation and evaluation will be established
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SYSTEMS ANALYSIS & DESIGN 3E
SOFTWEAR, LIMITED
The ESIP development team reviewed True Blue Systems’ design recommendation
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SYSTEMS ANALYSIS & DESIGN 3E
SOFTWEAR, LIMITED
The ESIP development team reviewed True Blue Systems’ design recommendation
The team then used a top-down approach to partition the system into a set of modules
Each module represented a program or function to be performed by one or more macros or code procedures
The team carefully reviewed all ESIP system tasks and prepared a structure chart
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SYSTEMS ANALYSIS & DESIGN 3E
SOFTWEAR, LIMITED Mainframe interface
Extract module tasks Prepare a design for the extract module Write the commands, using Visual Basic Unit test the ESIP program module with test
data, using stubs to indicate inputs and outputs
Verify the results Create a procedure for downloading the
deduction file from the mainframe to the ESIP server
Test the download procedure and update the documentation
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SYSTEMS ANALYSIS & DESIGN 3E
SOFTWEAR, LIMITED ESIP server
Database development tasks Finish switchboard and screen designs, with
user input, including custom menus & icons Design all necessary reports Verify ERDs record designs Define data tables, identify primary keys,
and link tables into a relational structure Load test data Design and test queries Design and test macros and code modules Complete work on security features
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SYSTEMS ANALYSIS & DESIGN 3E
SOFTWEAR, LIMITED
Completing application development ESIP design and unit testing was completed in
three weeks Link testing was performed successfully System testing revealed that several minor
changes and corrections were necessary All changes received user approval and were
documented carefully A user manual was developed, with substantial
input and participation from users themselves
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