Transaction Processing Systems and System Development Life Cycle

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Transaction Processing Systems andSystem
Development Life Cycle
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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
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TPSTransaction Processing Systems

• 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

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TPS vs. MIS/DSS and AI/ES
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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

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SDLC

• Systems Development Life Cycle
• Careers are made and taken away based on the
  outcome of system development.

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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

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Who are the players in SDLC?

• IT
• Manager Ultimately responsible for system.
  Handles
• Funding
• Communication with upper level management
• Resolves major issues
• Can manage several systems at any point in time
• Project Lead Head systems analyst
• 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

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Who are the players in SDLC?

• IT (cont)
• Systems Analyst
• Specializes in analyzing business problems and
  designing a system to resolve problems.
• Programmer
• Builds and modifies programs based on direction
  of systems analyst and project lead.

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Traditional SDLC

• Investigation
• Analysis
• Design
• Implementation
• Maintenance and Review

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SDLC Step 1 Investigation

• What is the problem and is it worth solving?
• Feasibility study may be created by IT
• Short, Inexpensive study
• Objective Define scope of problem, cost vs.
  benefits
• technical, operational, schedule, economic, legal
  feasibility
• End Result Systems Investigation report
• Continue on with project?
• Modify project?
• Drop it?
• Methods IT interviews business employees and
  observes current system and processes

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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!!!

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SDLC Step 3 Design

• How will the system solve the problem?
• Objective Develop detailed technical
  specifications for hardware, software, database,
  etc.
• End result
• 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.

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SDLC Step 4 Implementation

• 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

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Phases of Implementation

• 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
• Direct Cutover (manual work may also be done as a
  fail-safe)
• Phased In (most critical components first)
• Pilot (released to one area at a time)
• Parallel (old and new run together for a short
  time)

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SDLC Step 5 Maintenance/Review

• Objective Fix Bugs, add enhanced functions
• End Result Fully functional system
• User acceptance document
• Need to watch for changing business environment.
  Any enhanced functions should follow through the
  SDLC.

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Other things to consider

• Prototyping
• Portions of the system are developed
• May not be fully functional
• Feedback from users provides future direction
• Rapid Application Development (RAD)
• Uses tools and techniques designed to speed
  development
• JAD (Joint application development) involves
  heavy interaction of users and analysts.

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CASE Tools

• CASE Computer-Aided Software Engineering
• Tools that automate tasks in SDLC
• Upper-CASE tools
• Aid in early stages of SDLC (investigation,
  analysis and design)
• Lower-CASE tools
• Aid in later stages of SDLC (development,
  maintenance). Can generate code
• Integrated-Case tools
• Provide links between upper and lower. Can
  generate code based on data from analysis and
  design.