INFSY540

1. INFSY540 Chapter 12 Systems Development

2. Systems Analysis and Design • Systems Analysis • Tear system apart (destructive, in a way) • Systems Design • Put system together (creative, in a way) • Tear systems apart into their component parts to: • To really understand the simpler components. (Because it is too hard to understand the system as a whole.) • To put them back together better than they were before. • Systems Development = Systems Analysis + Design

3. Systems Analysis and Design • Requires a method or there will be madness. • Need to meet organization requirements without exceeding organizational constraints. • Identifying and articulating requirements is not easy. But it is absolutely essential. • Resources must be considered, otherwise you might not be able to get there from here.

4. Standards! Integrate Write code Build DB Find a problem Identify Management Functions and Operations Entire Organization Design Systems Data Programs Top-down and Bottom-up Management Functions Functions Operations Operations Operations Databases Databases Databases Databases Databases Programs Programs Programs Programs Programs Programs Programs Programs Programs

5. Runaway Projects • Technical measures • 2 - 5 times over budget • 2 - 5 times behind schedule • Missing technical objectives • Design problems • Duplication of efforts • Incompatibilities • User/designer conflicts $ 1994 1996 1998

6. Reasons for Success User Involvement Executive management support Clear requirements Proper planning Realistic expectations Reasons for Failure Lack of user input Incomplete requirements Changing requirements and specifications Lack of executive support Lack of technical skills Success & Failure Cafasso 1994

7. Projects • What are projects? • Out of the ordinary work. • A (temporary) sequence of activities having a common purpose that is supposed to be completed by a specified time, within budget and according to specifications.

8. How do you evaluate projects? • Criteria of projects • Technical Objectives • Operational Objectives • Schedule Objectives • Economic Objectives • Legal Objectives • Constraints of projects • Technical feasibility • Operational feasibility • Schedule feasibility • Economic feasibility • Legal feasibility Constraints Criteria Do Well Don’t Do Well Met Not Met Great Ok Bad Bad

9. Process versus Methodology A system development process is a set of activities, methods, best practices, deliverables, and automated tools that stakeholders use to develop and maintain information systems and software. A system development methodology is a very formal and precise system development process that defines a set of activities, methods, best practices, deliverables, and automated tools that system developers and project managers are to use to develop and maintain information systems and software.

10. Principles of System Development • Get the owners and users involved. • Use a problem-solving approach. • Establish phases and activities. • Establish standards. • Justify systems as capital investments. • Don’t be afraid to cancel or revise scope. • Divide and conquer. • Design systems for growth and change.

11. Life Cycles • What are they? • Give an example of a generic life cycle. • Why are they important to anyone creating systems? • When do people try to replace existing systems? • When do creatures replace themselves?

12. Life Cycles • What are they? • Give an example of a generic life cycle. • Why are they important to anyone creating systems? • When do people try to replace existing systems? • When they break, when they are dying? • When do creatures replace themselves? • When the creature is in its early maturity

13. Examples of Life Cycles

14. Systems Development Life Cycle Feasibility & Planning Goals & plans Systems Analysis Business requirements Systems Design Technical Design Proposal Systems Implementation Problems & Improvements New System revisions revisions Existing System problems problems Systems Maintenance: Incremental changes

15. Phases of a Representative Methodology

16. Project Identification and Initiation • Problems are undesirable situations that prevent the organization from fully achieving its purpose, goals, and/or objectives. • Opportunities are chances to improve the organization even in the absence of specific problems. • Directives are new requirements that are imposed by management, government, or some external influence.

17. The PIECES Problem-Solving Framework P performance I information E economics, costs, profits C control or security E efficiency of people and processes S service

18. Alternative Routes through a Methodology • Model-Driven Development (MDD) • Rapid Application Development (RAD) • Commercial Off-the-Shelf Software (COTS) • Maintenance and Reengineering or hybrids of the above

19. Model-Driven Development (MDD) Route

20. Rapid Application Development (RAD) Route

21. Commercial Off-the-Shelf (COTS) Software Route

22. Maintenance and Reengineering Route

23. Process and Project Managers • A process manager is an automated tool that helps to document and manage a methodology and routes, its deliverables, and quality management standards. • A project manager is an automated tool to help plan system development activities (preferably using the approved methodology), estimate and assign resources (including people and costs), schedule activities and resources, monitor progress against schedule and budget, control and modify schedule and resources, and report project progress.

24. Information Systems Architecture Information systems architecture provides a unifying framework into which various people with different perspectives can organize and view the fundamental building blocks of information systems.

25. Perspectives or Stakeholders • System owners pay for the system to be built and maintained. • System users use the system to perform or support the work to be completed. • System designers design the system to meet the users’ requirements. • System builders construct, test, and deliver the system into operation. • Systems analystsfacilitate the development of information systems and computer applications by bridging the communications gap that exists between nontechnical system owners and users and technical system designers and builders. • IT vendors and consultants sell hardware, software, and services to businesses for incorporation into their information systems.

26. Focuses for Information Systems • Data—the raw material used to create useful information. • Processes—the activities (including management) that carry out the mission of the business. • Interfaces—how the system interfaces with its users and other information systems.

27. Information System Building Blocks

28. Information System Building Blocks

29. Data Flow Diagram Show process and flow of data. Process No Increasingly detailed levels of process. Structure Chart or VTOC Show modules and usage flow. Module structure No By program structure or usage steps. Entity Relationship Diagram Describe Data structures. Yes By entities or object inheritance. Comparison of Diagrams Purpose, Classification, Object Orientation, Decomposition

30. SDLC Effort G. Davis and M. Olson, Management Information Systems 1985.

31. Systems Implementation • Final testing • Involve users • Education and training • Flexibility • Recognize how the system will affect the business • Encourage users to change • Implementation plans Education and training Changing Business operations

32. Implementation Options old new Direct cutover old Parallel new store 1 new Pilot new store 2 new store 3 new store 4 old new dept or component 1 dept or component 2 Phased dept or component 3 dept or component 4

33. Mission Goals Hardware/ software Database Telecommunications IS personnel Control Training Costs Complexity Reliability Efficiency Response time Documentation Factors to Consider During Systems Review

34. System Evaluation

35. Objects & Events Events Methods Objects Record Sale Update Inventory Notify Customer Service Transaction Log Accounts & Ledgers Inventory Customers Employees (commissions) Sale Accounts & Ledgers Suppliers Shipping/Receiving Inventory Order/JIT Notify Suppliers Schedule Payment Installation & Maintenance

36. Developing Systems with Teams Developing systems is generally a team effort among MIS developers and business users. Groupware, CASE, and development tools are often used to facilitate communication and coordination.

37. Teamwork Development Coordination Technology Information Sharing Change Monitoring Control Data Sharing Concurrency Control Consistency Enforcement Product User Access Control

38. End-user Development • Advantages • Faster • Cheaper • Get what you want • Disadvantages/Problems • Lack of documentation • Individual/personal differences • Pre-packaged software limitations • Takes User time

39. Many people use the system PC versus central computer Need documentation Individual user differences Need to train users Commercial software limits User time is expensive Mission critical application Additional testing Many modifications Need security & control Need to integrate Use corporate data Tie to existing software Connect to network Database Integrity Avoid duplicate data Changes to corporate data End-user DevelopmentWhen to Call for Help

40. MIS Size: Many users Complexity: Different departments Long development time SDLC large project controls Cost of user time Critical Information Major changes to central data base Formal testing Expensive hardware Formal feasibility Compatibility Specialized knowledge End User One-time code Can purchase pre-packaged solutions Highly trained users How Can MIS Help? Easy access to data/database Advice and help Testing & quality control Training & tutorials Information Center Who Should Develop Systems?

41. Programming Logic Computations Variables Internal functions Conditions Loops Input Output Appendix: Visual Basic Math functions Abs Absolute value Atn Arc Tangent Cos Cosine Exp Exponential Fix Returns integer portion Int Converts to integer Log Logarithm Rnd Random number Sgn Signum (-1, 0, 1) Sin Sine Sqr Square root Tan Tangent String functions StrComp Compare two strings LCase, UCase Convert to lowercase or uppercase Len Find length of a string Format Format a string InStr, Left, LTrim Mid, Right, RTrim, Trim Manipulate strings.

42. VB: Conditions If (condition) Then statements if true Else statements if false End If Select Case Customer Case Customer = ‘Corporate’ Discount = 0.05 Case Customer = ‘Government’ Discount = 0.10 Case Else Discount = 0.01 End Select If (Sales > 1000) Then Bonus = 100 Else Bonus = 0 End If

43. VB: Loops total = 0 For month = 1 To 12 total = total + SalesForMonth(month) Next month month = 0 sales = 0 Do Until (sales > 100000) sales = sales + SalesForMonth(month) month = month + 1 Loop

44. VB: Input and Output Could use: InputBox, MsgBox, and Printer object. Generally just use data in the application. In this example, the form collects the data and displays the result.

45. Sub Macro1() ' Keyboard Shortcut: Ctrl+Shift+U For Each c In Selection c.Value = PCase(c.Value) Next c End Sub VBA: Excel Example Function PCase(txt) ' Convert a text value to proper case Dim i As Integer txt = LCase(txt) Mid(txt, 1, 1) = UCase(Mid(txt, 1, 1)) i = 2 Do While (i > 0) And (i < Len(txt)) i = InStr(i, txt, " ") If (i > 0) And (i < Len(txt)) Then Mid(txt, i + 1, 1) = UCase(Mid(txt, i + 1, 1)) i = i + 1 End If Loop PCase = txt End Function