Transaction Processing Systems and System Development Life Cycle

1. Transaction Processing Systems andSystem Development Life Cycle

2. 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

3. TPS–Transaction 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

4. TPS vs. MIS/DSS and AI/ES

5. 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

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

7. 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

8. 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

9. 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.

10. Traditional SDLC • Investigation • Analysis • Design • Implementation • Maintenance and Review

11. 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

12. 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!!!

13. 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.

14. 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”

15. 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)

16. 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.

17. 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.

18. 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.