CIS 2303 LO1: Introduction to System Analysis and Design
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CIS 2303 LO1: Introduction to System Analysis and Design
- 1. Systems Analysis and Design CIS 2303 Learning Outcome 1: Describe the evolution of software development with emphasis on the processes that outline different methodologies. - Ch. 1
- 2. Learning Objectives 1. Introduction to Information Systems Discuss the impact of information technology on business strategy and success Define an information system and describe its components Explain how profiles and models can represent business functions and operations 2. Systems Development Methods 3. Overview of Structured Analysis and SDLC 4. SDLC MODEL Phases 2
- 3. 1. Introduction to Information Systems A. Chapter Introduction Case: Mountain View College Bookstore B. Discuss the impact of information technology on business strategy and success C. What is IT? D. What is Systems analysis and design? E. Define an information system and describe its components F. Explain how profiles and models can represent business functions and operations 3
- 4. B. Impact of IT on business strategies • Companies use information as a weapon in the battle to increase productivity, deliver quality products and services, maintain customer loyalty, and make sound decisions • Information technology can mean the difference between success and failure • Figure 1-1 4
- 5. C. What is IT? Information Technology (IT) ◦ Combination of ___________and ___________ products and ___________ that ___________ use to manage, access, communicate, and share ____________ 5 companies hardwar e informatio n softwar e service s
- 6. D. Systems Analysis and Design Systems Analysis and Design Step-by-step process for developing high- quality information systems Roles of the Systems Analyst Plan, develop, and maintain information systems See the next slides to have a detailed list of the Systems analyst. 6
- 7. Roles of the Systems Analyst The primary objective of any system analyst is to identify the need of the organization by acquiring information by various means and methods. The system analyst has to coordinate with the: ◦ _________________, ◦ _________________, ◦ ___________________________________ ____________________________________. Following are the tasks performed by the systems analyst: 7
- 8. Tasks Performed By the Systems Analyst Defining Requirement: Prioritizing Requirements Gathering Facts, data and opinions of Users Evaluation and Analysis Drawing Specifications 8
- 9. Defining Requirement: The basic step for any system analyst is to understand the requirements of the users. This is achieved by various fact finding techniques like: ◦ interviewing, ◦ observation, ◦ questionnaire ◦ etc. 9
- 10. Prioritizing Requirements Number of users use the system in the organization, and each one has a different requirement and retrieves different information. Due to certain limitations in computing capacity it may not be possible to satisfy the needs of all the users. Hence it is important to create list of priorities according to users requirements. 10
- 11. Gathering Facts, data and opinions of Users After determining the necessary needs and collecting useful information, the analyst starts the development of the system with active cooperation from the users of the system. Time to time, the users update the analyst with the necessary information for developing the system. The analyst while developing the system continuously consults the users and acquires their views and opinions. 11
- 12. Discussion As a System’s Analyst, why do you need to continuously consult the users and acquires their views and opinions?
- 13. Evaluation and Analysis The analyst must constantly change and modify the system to make it better and more user friendly for the users 13
- 14. Drawing Specifications The analyst must draw certain specifications which will be useful for the manager. The analyst should lay the specification which can be easily understood by the manager and they should be purely non-technical. The specifications must be in detailed and in well presented form 14
- 15. E. Information System Components • Information systems have five key components: • hardware, • software, • data, • processes, and • People 15
- 16. E. Information System Components –Cont. 1. Hardware ◦ Is the physical layer of the information system ◦ Moore’s Law 2. Software ◦ System software ◦ Application software 16
- 17. E. Information System Components –Cont. 3. Data ◦ Tables store data ◦ Linked tables work together to supply data 17
- 18. E. Information System Components –Cont. 4. Processes ◦ Describe the tasks and business functions that users, managers, an d IT staff members perform to achieve specific results 5. People ◦ Stakeholders ◦ Users, or end users 18
- 19. Information System Components Exercise Microsoft Windows Number of Hours Worked Register a Student Microsoft Excel Storage Server Withdraw Cash System Users Employee No Hardware Software Data Processes People 19
- 20. 2. Systems Development Methods Systems Development Methods ◦ Structured Analysis ◦ Object-Oriented Analysis ◦ Agile/adaptive methods In this course, we will only concentrate on the Structured Analysis. 20
- 21. 3. Overview of Structured Analysis and SDLC Model A traditional systems development technique that is time-tested and easy to understand. Uses a series of phases, called the systems development life cycle (SDLC ), to plan, analyze, design, implement, and support an information system. A Predictive approach Structured analysis is called a process-centered technique 21
- 22. 3. Overview of Structured Analysis and SDLC Model –Cont. In the waterfall model , the result of each phase is called a deliverable , or end product , which flows into the next phase. Disadvantage in the built-in structure of the SDLC, because the waterfall model does not emphasize interactivity among the phases This criticism can be valid if the SDLC phases are followed too rigidly Adjacent phases usually interact See Figure 1-27 22
- 23. 4. SDLC MODEL Phases The SDLC model usually includes five steps 1) Systems planning 2) Systems analysis 3) Systems design 4) Systems implementation 5) Systems support and security See Figure 1-27 in the next slide 23
- 24. Figure 1-27: SDLC – The Waterfall Model 24 Phase 1 Systems planning Phase 2 Systems Analysis Phase 3 Systems Design Phase 4 Implementation Phase 5 Operation, Support & Security
- 25. Planning and Modeling a Systems Development Project Systems planning ◦ Systems request ◦ Purpose of this phase is to perform a preliminary investigation whose key part is a feasibility study Systems Analysis ◦ The purpose is to build a logical model of the new system. ◦ The first step is requirements modeling , where you investigate business processes and document what the new system must do to satisfy users. ◦ Requirements modeling continues the investigation that began during the systems planning phase. ◦ Deliverable is the System requirements document which describes management and Preliminary Investigation Report System Requirements Document
- 26. Planning and Modeling a Systems Development Project Systems Design ◦ The purpose is to create a physical model that will satisfy all documented requirements for the system. ◦ At this stage, you design the user interface and identify necessary outputs, inputs, and processes ◦ Deliverable is system design specification ◦ Management and user involvement is critical Systems Implementation ◦ New system is constructed ◦ Programs are written, tested, and documented, and the system is installed ◦ The objective is to deliver a completely functioning and documented information system ◦ Final preparations include converting data to the new system's files and training users ◦ This stage also includes an assessment, called a systems evaluation System Design Specs Functional IS
- 27. Planning and Modeling a Systems Development Project Systems Operation, Support, and Security ◦ A well-designed system must be secure, reliable, maintainable, and scalable ◦ After several years of operation, systems need extensive changes ◦ During this phase, the IT staff maintains, enhances, and protects the system ◦ Security controls safeguard the system from both external and internal threats Operational IS
- 28. I am designing the user interface of the system and the database that the system will use to store the user’s data! (______________________) I am gathering the system requirements of the user through interviews, questionnaires, and observation at work! (______________________) I am adding more forms and reports to the system that users asked me to add because they have new requirements! (______________________) I am doing a Preliminary Investigation and a Feasibility Study to investigate the “Worthiness” of the proposed system! (______________________) I am writing the programming code of the system! (______________________) 28 Which SDLC Model Phase am I in?!
- 29. Review Questions (Answer on BB-Learn) What is IT, and why is it important to a business? What is the role of the System Analyst? What are three different Systems Development Methods? What are the different functions of a business? What are the phases of the SDLC? What are the different activities within an IT department? What is an IS, and what are its components?
Notas del editor
- The headlines in Figure 1-1 offer dramatic examplesof how information technology affects our society.Companies use information as a weapon in the battleto increase productivity, deliver quality productsand services, maintain customer loyalty, and makesound decisions. In a global economy with intensecompetition, information technology can mean thedifference between success and failure.
- The headlines in Figure 1-1 offer dramatic examplesof how information technology affects our society.Companies use information as a weapon in the battleto increase productivity, deliver quality productsand services, maintain customer loyalty, and makesound decisions. In a global economy with intensecompetition, information technology can mean thedifference between success and failure.
- More than ever, business success depends on information technology. IT is driving a new digital economy, where advances in hardware, software, and connectivity can provide enormous benefits to businesses and individuals. Although economic trends affect IT spending levels, most firms give IT budgets a high priority, in good times or bad. The reason is simple — during periods of growth, companies cannot afford to lag behind the IT curve. Conversely, when the economy slows down, firms often use IT to reduce operating costs and improve efficiency.
- Systems analysis and design is a step-by-step process for developing high-quality information systems. An information system combines information technology, people, and data to support business requirements. For example, information systems handle daily business transactions, improve company productivity, and help managers make sound decisions. The IT department team includes systems analysts who plan, develop, and maintain information systems.
- Hardware purchasers today face a wide array of technology choices and decisions. In 1965, Gordon Moore, a cofounder of Intel, predicted that the number of transistors on an integrated circuit would double about every 24 months. His concept, called Moore's Law , has remained valid for more than 50 years. Fortunately, as hardware became more powerful, it also became much less expensive. Large businesses with thousands or millions of sales transactions require company-wide information systems and powerful servers.
- System software manages the hardware components, which can include a single workstation or a global network with many thousands of clients. Either the hardware manufacturer supplies the system software or a company purchases it from a vendor. Examples of system software include the operating system, security software that protects the computer from intrusion, device drivers that communicate with hardware such as printers, and utility programs that handle specific tasks such as data backup and disk management. System software also controls the flow of data, provides data security, and manages network operations. In today's interconnected business world, network software is vitally important.Application software consists of programs that support day-to-day business functions and provide users with the information they require. Application software can serve one user or thousands of people throughout an organization. Examples of company-wide applications, called enterprise applications , include order processing systems, payroll systems, and company communications networks. On a smaller scale, individual users increase their productivity with tools such as spreadsheets, word processors, and database management systems.
- Data is the raw material that an information system transforms into useful information. An information system can store data in various locations, called tables. By linking the tables, the system can extract specific information. Figure above shows a payroll system that stores data in four separate tables. Notice that the linked tables work together to supply 19 different data items to the screen form. Users, who would not know or care where the data is stored, see an integrated form, which is their window into the payroll system.
- Processes describe the tasks and business functions that users, managers, and IT staff members perform to achieve specific results. Processes are the building blocks of an information system because they represent actual day-to-day business operations. To build a successful information system, analysts must understand business processes and document them carefully.People who have an interest in an information system are called stakeholders . Stakeholders include the management group responsible for the system, the users (sometimes called end users ) inside and outside the company who will interact with the system, and IT staff members, such as systems analysts, programmers, and network administrators who develop and support the system.Each stakeholder group has a vital interest in the information system, but most experienced IT professionals agree that the success or failure of a system usually depends on whether it meets the needs of its users. For that reason, it is essential to understand user requirements and expectations throughout the development process.
- Structured analysis is a traditional systems development technique that is time-tested and easy to understand. Structured analysis uses a series of phases, called the systems development life cycle (SDLC ), to plan, analyze, design, implement, and support an information system. Although structured analysis evolved many years ago, it remains a popular systems development method. Structured analysis is based on an overall plan, similar to a blueprint for constructing a building, so it is called a predictive approach.Structured analysis uses a set of process models to describe a system graphically. Because it focuses on processes that transform data into useful information, structured analysis is called a process-centered technique. In addition to modeling the processes, structured analysis also addresses data organization and structure, relational database design, and user interface issues.A process model shows the data that flows in and out of system processes. Inside each process, input data is transformed by business rules that generate the output.
- Some analysts see a disadvantage in the built-in structure of the SDLC, because the waterfall model does not emphasize interactivity among the phases. This criticism can be valid if the SDLC phases are followed too rigidly. However, adjacent phases usually interact,and interaction among several phases is not uncommon. Other analysts regard the waterfall model as a two-way water flow model, with emphasis on iteration and user input. Used in this manner, the traditional model is not as different from agile methods as it might appear to be.To have a brief about the major differences between the three methodologies. See the textbook (Ch.1 Page 21)
- The SDLC model usually includes five steps, which are described in the following sections: systems planning, systems analysis, systems design, systems implementation, and systems support and security.
- The purpose of the systems analysis phase is to build a logical model of the new system. The first step is requirements modeling , where you investigate business processes and document what the new system must do to satisfy users. Requirements modeling continues the investigation that began during the systems planning phase. To understand the system, you perform fact-finding using techniques such as interviews, surveys, document review, observation, and sampling. You use the fact-finding results to build business models, data and process models, and object models. The deliverable for the systems analysis phase is the system requirements document . The system requirements document describes management and user requirements, costs and benefits, and outlines alternative development strategies.
- The purpose of the systems design phase is to create a physical model that will satisfy all documented requirements for the system. At this stage, you design the user interface and identify necessary outputs, inputs, and processes. In addition, you design internal and external controls, including computer-based and manual features to guarantee that the system will be reliable, accurate, maintainable, and secure. During the systems design phase, you also determine the application architecture, which programmers will use to transform the logical design into program modules and code.The deliverable for this phase is the system design specification , which is presented to management and users for review and approval. Management and user involvement is critical to avoid any misunderstanding about what the new system will do, how it will do it, and what it will cost.---------During the systems implementation phase , the new system is constructed. Whether the developers use structured analysis or O-O methods, the procedure is the same — programs are written, tested, and documented, and the system is installed. If the system was purchased as a package, systems analysts configure the software and perform any necessary modifications. The objective of the systems implementation phase is to deliver a completely functioning and documented information system. At the conclusion of this phase, the system is ready for use. Final preparations include converting data to the new system's files, training users, and performing the actual transition to the new system.The systems implementation phase also includes an assessment, called a systems evaluation , to determine whether the system operates properly and if costs and benefits are within expectations.
- SYSTEMS SUPPORT AND SECURITYDuring the systems support and security phase , the IT staff maintains, enhances, and protects the system. Maintenance changes correct errors and adapt to changes in the environment, such as new tax rates. Enhancements provide new features and benefits. The objective during this phase is to maximize return on the IT investment. Security controls safeguard the system from both external and internal threats. A well-designed system must be secure, reliable, maintainable, and scalable. A scalable design can expand to meet new business requirements and volumes. Information systems development is always a work in progress. Business processes change rapidly, and most information systems need to be updated significantly or replaced after several years of operation.