Transaction Processing Systems
and
System Development Life Cycle
An organization's transaction
processing systems (TPSs) must
support the routine, day-to-day
activities that occur in the normal
course of business and help a
company add value to its
products and services
TPS–Transaction Processing Systems
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Process detailed data for fundamental
business operations
Provides data for the MIS/DSS/AI/ES
systems
On-line Transaction Processing (OLTP) –
transaction is processed immediately
Batch Processing – transactions are
accumulated and processed at one time
TPS vs. MIS/DSS and AI/ES
Transaction Processing Cycle
Basic data processing activities…
 Data Collection: capture all necessary data
 Data Editing: check for validity of data
 Data Correction: prompt for reentry of data
 Data Manipulation: perform any necessary
calculations on data
 Data Storage: update database with data
SDLC
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Systems Development Life Cycle
Careers are made and taken away based on
the outcome of system development.
Who are the players in SDLC?
Business:
 Stakeholders: employees who should
benefit from the system
 Users: employees using the system
 Business Owners: employees playing an
active role in developing the system
Who are the players in SDLC?
IT:
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Manager: Ultimately responsible for system. Handles
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Funding
Communication with upper level management
Resolves major issues
Can manage several systems at any point in time
Project Lead: Head systems analyst
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Reports to manager
Manages all day to day activity for system
Determines schedule (could be determined by outside forces)
Main contact for stakeholders and users
Who are the players in SDLC?
IT (cont):
 Systems Analyst:
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Specializes in analyzing business problems
and designing a system to resolve problems.
Programmer:
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Builds and modifies programs based on
direction of systems analyst and project lead.
Traditional SDLC
1.
2.
3.
4.
5.
Investigation
Analysis
Design
Implementation
Maintenance and Review
SDLC – Step 1: Investigation
What is the problem and is it worth solving?
 Feasibility study may be created by IT
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Short, Inexpensive study
Objective: Define scope of problem, cost vs. benefits
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technical, operational, schedule, economic, legal feasibility
End Result: Systems Investigation report
Continue on with project?
 Modify project?
 Drop it?
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Methods: IT interviews business employees and
observes current system and processes
SDLC – Step 2: Analysis
Most critical step
What must the system do to solve the problem?
 Objectives: Detailed business/functional requirements
 End Results: Logical requirements (Data Model,
Flowcharts, expected volume, etc.)
 Methods: Interviews, Data Collection and Analysis,
Data-flow diagrams
 Everyone must spend the necessary time here,
planning is everything. All parties should review
results (IT and Business). NO CHANGES
SHOULD BE MADE TO THE SPECS AFTER
THIS!!!
SDLC – Step 3: Design
How will the system solve the problem?
 Objective: Develop detailed technical specifications
for hardware, software, database, etc.
 End result:
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Make or buy?
RFP (Request for Proposal)
Program, interface and response time specs
Methods: IT uses technical knowledge to create
requirements. Small amount of input from business
organization. Freeze is placed on Design.
SDLC – Step 4: Implementation
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Objective: A system delivered to the business
users
End result: System works correctly, users are
trained
IT will provide status updates to Business
Any changes made to the system during this
phase will need more time/money.
“Given time and money, anything is possible”
Phases of Implementation
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Purchase of Hardware/Software
Programming
Testing (Initially by IT and then by Business users)
Training (Done by IT and Business users)
Conversion from old to new system:
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Direct Cutover (manual work may also be done as a failsafe)
Phased In (most critical components first)
Pilot (released to one area at a time)
Parallel (old and new run together for a short time)
SDLC – Step 5: Maintenance/Review
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Objective: Fix “Bugs”, add enhanced functions
End Result: Fully functional system
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User acceptance document
Need to watch for changing business
environment. Any enhanced functions should
follow through the SDLC.
Other things to consider…
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Prototyping:
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Portions of the system are developed
May not be fully functional
Feedback from users provides future direction
Rapid Application Development (RAD):
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Uses tools and techniques designed to speed
development
JAD (Joint application development) involves heavy
interaction of users and analysts.
CASE Tools
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CASE: Computer-Aided Software Engineering
Tools that automate tasks in SDLC
Upper-CASE tools:
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Lower-CASE tools:
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Aid in early stages of SDLC (investigation, analysis and
design)
Aid in later stages of SDLC (development, maintenance).
Can generate code
Integrated-Case tools:
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Provide links between upper and lower. Can generate code
based on data from analysis and design.