2. Chapter 10 Systems Planning, Analysis, and Design

3. Presentation Summary I.The Steps of Systems Analysis II.Fact-Gathering Techniques III.Techniques for Organizing Facts IV.Structured Systems Analysis V.The Steps of Systems Design

4. I. The Steps of Systems Analysis A.Survey the Present System B.Identify Information Needs C.Identify System Requirements D.Develop a Systems Analysis Report

5. A. Survey the Present System Four objectives of the system survey are concerned with: 1.Understanding the Operational Aspects of the Current System 2.Establishing a Working Relationship with System Users 3.Collection of Data for Systems Design 4.Identification of Specific System Problems

6. 1. Understanding the Operational Aspects of the Current System It is dangerous to try to modify an existing system that you do not thoroughly understand. The strengths and weaknesses of the current system must be identified before modifying the system.

7. 2. Establishing a Working Relationship with System Users Get to know the people involved in the system as soon as possible. Communicate the benefits of the new system. Provide assurance, when possible, of job security and no changes in job responsibilities. Project a genuine concern for making the life of the system user better. The success or failure of a systems project largely depends on the relationship between the development team and the people who use the system.

8. 3. Collection of Data for Systems Design Internal data may be collected from sources like interviews, questionnaires, observations, and policy manuals. Outside data may be collected from industry publications, professional journals, and customers.

9. 4. Identification of Specific System Problems Effectiveness considers whether the system meets its objectives. Efficiency determines whether objectives are met at the lowest possible cost. Evaluation of the system should also consider bottlenecks. These are areas where small changes could result in major improvements.

10. B. Identify Information Needs Identify the managers primary job responsibility. Identify the means by which the manager is evaluated. Identify some major problems the manager faces. Identify the way the manager evaluates personal output. Managers often have difficulty in expressing just how they make decisions. Identification of the above areas can be helpful in pinpointing a manager’s decision process. Identification of problems may be best done by simply getting the manager talking while you listen.

11. C. Identify the System Requirements Requirements can be specified in terms of inputs and outputs. First determine the required outputs that a manager needs to make a decision. Then determine the inputs and processing needed to generate the outputs.

12. D. The Systems Analysis Report Description of the overall problems in subsystem being studied Recommendations for improving existing system or design of new system. Overall cost budget and timetable for project to date. The report should organize and document the first three phases of analysis. Some key elements of the report include:

13. II. Fact-Gathering Techniques A.Fact Gathering Through Interviews B.Fact Gathering Through Questionnaires

14. A. Fact Gathering Through Interviews 1. Depth Interviews - Conversation is guided largely by feelings and interest of the person being interviewed. 2.Structured Interviews - Useful after a depth interview for obtaining answers to a specific set of questions.

15. B. Fact Gathering Through Questionnaires 1. Open-Ended Questionnaires - Persons provide written answers to general rather than specific questions. 2. Closed-End Questionnaires - Use for routine situations or when a large number of similar individuals would be questioned. What types of information do you use to make decisions?

16. III. Structured Systems Analysis A.Structured Systems Analysis Defined B.The Development of Logical Data Flow Diagrams C.Defining Data Dictionaries D.Defining Access Methods E.Defining Process Logic

17. A. Structured Systems Analysis Defined Structured systems analysis is a system of documentation. An approach to systems analysis that begins with a very general description of a particular system, and then moves to ever increasing detail ending with computer program code and other details.

18. B. The Development of Logical Data Flow Diagrams 1.Data Flow Diagram Levels 2.Data Flow Diagram Symbols 3.Data Flow Diagram Conventions

19. 1. Data-Flow Diagram Levels Context Diagrams represent the highest level of data-flow diagrams. More detail is provided in subsequent diagrams beginning at level zero. 0 Purchasing System Stores Requisition Purchase Order Purchase Details Purchase File Purchase File Context Diagram Vendors

20. 1. Data-Flow Diagram Levels 1.0 Validate Requisition Stores Requisition Details Purchase Details Purchase File Purchase File Vendors 2.0 Prepare Purchase Order Purchase Order (Continued)

21. 2. Data-Flow Diagram Symbols  Sources and destinations of data and information are shown in rectangular symbols around the process symbol.  Process symbol(s) in center of diagram identify system(s) under investigation.  Data flow lines describe the input data to the system and the output reports from the system.

22. 3. Data Flow Diagram Conventions Each process must have at least one input data flow and one output data flow. A data flow has at least one end connected to a process A diagram should not contain more than seven processes before being leveled into more detailed diagrams.

23. C. Defining Data Dictionaries The data dictionary corresponds to the data stores referenced in the logical data flow diagrams. This involves giving a description of the data structure and data elements involved.

24. D. Defining Access Methods It is necessary to specify how data stores will be accessed. This typically involves defining primary and secondary access keys. For example, in the purchase file the “account-no-1” may serve as the primary key and “person responsible” as the secondary key. Purchase File Description Account – Identifiers account-no-1 … primary account number account-no-2 … secondary account number person-responsible … person in charge of account Financial-Information account-balance … current balance last – purchase … most recent transaction

25. E. Defining Process Logic There are a number of different approaches to documenting the process logic, including decision trees and structured English. Structured English is a special language for describing process logic that uses several key words, including IF, THEN, ELSE IF, and SO. Structured English does not include provisions for error conditions and data file access. If these are added, the resulting documentation is pseudocode. See pseudocode for a C++ program on the following slide.

26. Pseudocode for A C++ Program

27. V. Steps in Systems Design A.Evaluation of Design Alternatives B.Preparation of Detailed Design Specifications C.Preparation of Systems Design Report

28. A. Evaluation of Design Alternatives There are usually a number of attractive solutions that could be chosen. Completely new systems may be designed from scratch or a pre-made system could be recommended. Alternative systems should be documented with information concerning advantages/disadvantages and cost information. A given system must be feasible from both an operational and technical perspective.

29. B. Preparation of Detailed Design Specifications Reports and Other Outputs Reports and Other Outputs Database Design Database Design Specify Processing Specify Processing Specify Inputs Specify Inputs Control Considerations Control Considerations 3. Once these decisions have been made, the designer then builds in the appropriate controls. 2. Once all the outputs are specified, the data inputs and processing steps are automatically determined. 1. Working with system objectives, the designer should design all management reports and operational output documents.

30. C. Preparation of Systems Design Report The completed design specifications should take the form of a proposal. Contents include timetables for completion, a budget, personnel requirements, and diagrams of the system to be implemented.

31. Summary Four Steps of Systems Analysis Gathering Information Through Interviews and Questionnaires Structured Systems Analysis as a Form of Documentation Detailed Design Specifications