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Basic Concepts of system Chapter 2 PP.pptx
- 1. BASIC CONCEPTS OFSYSTEM ANALYSIS AND DESIG CORE CONCEPTS ARE:- SYSTEMS ANALYSIS AND DESIGN APPROACHES TO SYSTEMS ANALYSIS AND DESIGN ROLE OF THE SYSTEM ANALYST SYSTEMS DEVELOPMENT LIFE CYCLE (SDLC) APPROACHES FOR DEVELOPMENT Chapter 2
- 2. Basic concepts ofSystem Analysis and Desig Systems Analysis:- -is the study of a business problem domain (area) for the purpose of recommending improvements and specifying the business requirements for the solution.
- 3. Cont… Systems Design:- -isthe specification or construction of a technical, computer based solution for the business requirements identified during systems analysis.
- 4. Cont… Systems Analysisand Design (SAD):- -is a method used by companies to create and maintain information systems that perform basic business functions.
- 5. Cont… The main goalof SAD Help to improve organizational systems through developing or acquiring application software that can help employees accomplish key business tasks more easily and efficiently. Application software is designed to support a specific organizational function or process, such as inventory management, payroll. The goal of application software is to turn data into information.
- 6. Cont… An InformationSystem is developed by following Software Engineering Process, which consists of proven methodologies, techniques and tool. These three process work together to form an organization approach to SAD. Figure 1. Software Engg. Process
- 7. Cont… Methodologies aresequence of step by step approaches that helps to develop the final product. Methodologies incorporate techniques like, direct observations and interviews with users. Techniques provide support for a wide range of tasks including conducting interviews with users, planning and managing the activities of a project and designing the reports. Tools are computer programs, such as computer aided software engineering (CASE) tools, that make it easy to use specific techniques.
- 8. Cont… Approaches toSystems Analysis and Design Every Information System consists of three key components that anyone who analyzes and designs must understand, they are data, data flows and processing logic. 1/ Data:- are raw facts that describe people, objects and events in an organization. Example. Customers account no, account type, balance amount. 2/ Data flow: - are groups of data that move and flow through a system Example: - customers account number is captured when he uses a credit card for purchase. 3/ Processing Logic : - describes the steps that transform the data and the events that trigger these steps Example:- processing logic in a credit card bill preparation
- 9. Cont… Process Orientedapproach Traditionally, Systems Analysts designed an Information System based on what the system was meant to do, such as billing or inventory control. The focus was on outputs and processing logic, in other words, on the flow, use and transformation of data. The data used as inputs were seen as important also, but secondary to the application Each system would contain its own files and data storage areas The data in each system would match the specifications for that system only Each systems was considered ( looked at) separately The analysis involved in creating drawings / diagrams that show how the data moves around the system and where it is stored in between flows.
- 10. Cont… The problemswith this approach are, first the existence of several files of data each locked with different applications and programs. Second, many of the files in different applications contains same data, updating the data becomes tedious process, it also difficult to combine data files created for specific applications. Figure-3: Process Oriented Approach
- 11. Cont… Data Orientedapproach Over time the approach changed to being a more data-oriented. This was a response to the problems above This approach tends to focus on how the data should be represented independently of where and how data are used in the system A data model is produced, which describes the data and relationships between the data. Business rules define how the organization deals with the data Databases are designed around the subjects such as customers, suppliers, parts. This lets use the dame databases for many different applications This means that the application is independent of data and data definitions it is called as application independence
- 12. Cont… Systems Integration approach Today, systems development focuses on systems integration. Systems integration allows hardware and software from different vendors to work together in an application. Figure-4: Data Oriented Approach
- 13. Cont… Role ofthe System Analyst A system analyst bridges the communication gap between those who need the information system and those who understand the technology A system analyst facilitates the study of the problems and needs of a business to determine how the business systems and information technology can best solve the problem and accomplish improvements for the business. Involving End users – it is important to include the people (users or end users) who are involved in the system. Since, They use the system, or will use the new system They know about the data and / or processes in the system They require reports from the system Involving mangers – managers in the business also need to be considered, since They define the business goals for projects They need to know what resources are required for a project They need to know how long the project will take They make the decisions
- 14. Cont… To succeedas a systems analyst, the skills needed are analytical, technical, managerial and interpersonal. Analytical skill enables to understand the organization and its functions, to identify opportunities and problems and to analyze and solve problems Technical skill helps to understand the potential and limitations of information technology. Must be able to work with programming languages and operating systems. Managerial skill helps to manage project, resources, risk and changes. Interpersonal skill enables to work with end users as well as other analysts and programmers. Effective written and oral communication skills: - a system analyst plays a major role as liaison (connection) among users, programmers and other analyst. Hence effective written and oral communication skill, including competence in leading meetings, interviewing end users, and listening are very much required.
- 15. Cont… System developmentlife cycle (SDLC) The series of steps used to mark the phases of development for an information system. It is a common methodology for systems development Figure-4: Software Development Life Cycle Like any other processes, the development of information system is too follows a life cycle Example: - a commercial product such as a Maruthi car follows a life cycle: It is created, tested and introduced to the market. Its sales increase, peak and decline. Finally the product is removed from the market and replaced by something else. The life cycle of an information system may as follows. Someone has idea for an information system and what it should do. A careful study is done of how the organization currently handles the work the system will support. Professionals develop a strategy for designing the new system, which is then either built or purchased. Once complete, the system is installed in the organization, and after proper training, the users begin to incorporate the new system into their daily work.
- 16. Cont… The commonfour SDLC steps are:- 1) Planning and selection 2) Analysis 3) Design and 4) Implementation and operation. The specific steps and their sequence are meant to be adapted as required for a project, if necessary the project can return to an earlier phase. Some activities in one phase in parallel with some activities of another phase. Sometimes the life cycle is iterative. Each phase has specific outcomes and deliverables that feed important information to other phase. These deliverables are reviewed by parties outside the project team, including managers and executives.
- 17. Cont… The SDLCis a structured approach; it uses data- oriented approach. Figure-5: Software Development Life Cycle- Detailed
- 18. Cont… Systems Planningand Selection The first phase in the SDLC has two primary activities Requests to deal with problems in current procedures The desire to perform additional tasks The realization that information technology could be used to improve the organization The Systems analyst prioritizes and translates the needs into a written plan including a schedule for developing new systems. The organization may decide whether or not the resources devoted for the project and a careful feasibility study is conducted to determine the economic and organizational impact of the system The second task is Investigating the system and determining the proposed system’s scope. Then a specific plan for the proposed project for the team to follow is produced. This Baseline Project Plan customizes the standardized SDLC and specifies the time and resources needed for its execution .
- 19. Cont… Systems Analysis Ithas three sub phases, First determine the requirements of the system, ie, what the users want from a proposed system. Second the requirements gathered are structured (DFD, ERD) according to their interrelationships, eliminating the redundancies . Third, system analyst has to generate alternative initial designs to match the requirements, best suited design is selected for the development after the comparison of all alternative designs.
- 20. Cont… Systems Implementation andoperation In this phase the information system is coded, tested and installed in the organization, and in which the information system is systematically repaired and improved. This phase also includes the initial training to the users and documentation of the system documented throughout the life cycle. During operation part, the problems faced by the users should be solved, and changes and enhancements (new versions) is to be made as per the users’ desire to reflect changing business conditions.
- 21. Cont… Systems Design Converts the description of recommended solution into logical and physical designs Logical design involves in designing the user interface, databases and compute processes, irrespective of the programming languages ( Algorithms, input and output forms, reports, table normalization) Physical design, the analyst team decides the programming language, database systems to be used, hardware platform, operating systems and network environment. The final outcome of the design phase is the physical system specifications, presented in the form such as a diagram or written report ready to be turned over to programmers and other system builders for construction.
- 22. Cont… Approaches forDevelopment The are four approaches that streamline and improve the systems analysis and design process. 1/ Prototyping, 2/ rapid application development(RAD), 3/ Joint application design(JAD) and 4/ Participatory design (PD) Prototyping. Prototyping is a key tool that supports rapid application development. RAD involves gaining user acceptance of the interface and developing key system capabilities as quickly as possible. Joint Application Design A structured process in which users, managers and analysts work together for several days in a series of intensive meetings to specify or review system requirements. Participatory design (PD) involves users in the development process, they have an equal voice in determining system requirements and in approving system design. ***