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HOW TO PHYSICALLY DESIGN A COMPUTER BASED INFORMATION SYSTEM
- 1. Group members Ehsan Ulla Khan Rimsha Akhtar Rebekah Samuel Muhammad Faheem Mehmood Muhammad Ali Hassan BBA 4TH A Date: 3 July 2018
- 2. HOW TO PHYSICALLY DESIGN A COMPUTER BASED INFORMATION SYSTEM
- 3. HOW TO PHYSICALLY DESIGN A COMPUTER BASED INFORMATION SYSTEM 1. Purpose and objectives of the physical design phase: • First the analyst seeks to design a system that both fulfill requirement and will be friendly to its end users. • Second and still very important the analysts seeks to present clear and complete specifications to the computer programmers and technicians. 2. End users should be involve in the physical data phase: • End users should be intimately involved in the physical design phase. • Requirements are transformed into computer inputs, outputs, files/ databases, and program specifications, • The end users should at least review key components.
- 4. 3. Ensure physical design consistency with the business: • The analyst’s principal concern during the design phase is to ensure that the subsequent design remains constant with business directions. 4. Fulfill current and projected functional requirements: • The analysts should have defined functional requirements long before systems design. • Ensure that the design fulfills those requirements. • Additional requirements may be introduced during the system design because a computer is used. • Edit reports for input data and audit trails for transactions are typically added to the basic user defined requirements. 5. Design all information system components: 1. Data and information: Specified the content of each data and information flow . we specified the media during the media during the selection phase. Now we need to physically design the style, organization, and format of all inputs and outputs. 2. Data stores: We must specify format, organization, and access methods for all files and databases to be used in the computer based system.
- 5. 3. End users: The roles people must play in the new system must be specified. For instance, who will capture and input data? Who will receive outputs? 4. Methods and procedures: The sequence of steps and flow of control must be specified. 5. Computer equipment: The specific hardware configurations specified during the selection phase must be considered as various other components are designed. 6. Computer program: Complete programming specifications must be prepared for every program that must be written or modified. 7. Internal controls: We must specify internal controls to ensure the security and reliability of the system.
- 6. HOW TO COMPLETE THE PHYSICAL DESIGN PHASE 1. Task: design computer files and/ or databases We must design the corresponding computer files and/or databases. Physical design goes far beyond the simple layout of the records. Designing files and databases that are adaptable to future requirements and expansion. Design include record size and storage volume requirement. 2. Task: design computer outputs In this task we must format each of those outputs. Transaction outputs will frequently be designed as preprinted forms onto which transaction details will be printed. 3. Task: design computer inputs Files and databases are maintained through the timely and accurate input of data. Any time you input data you can make mistakes. We need to define editing controls to ensure the accuracy of input data.
- 7. 4. Task: design the on-line user interface The idea behind user interface design is to build an easy to learn and use dialogue around the online input and output screens that were designed in earlier tasks. We are trying to make it easy for the end-user to understand what the screen is displaying at any given time. 5. Task: design methods and procedures The general procedures to be used in the new systems were approved during the selection phase. The internal controls from the previous tasks must be integrated into the new systems work flow. The timing of scheduled reports and transactions processing must be clearly specified. 6. Task: design computer program specifications this task packages all of the specifications from the previous tasks into computer program specifications that will guide the computer programmer’s activities during the constructive phase of the systems development lifecycle.
- 8. 7. Task: present and review the design Before the design can be presented, you need to prepare two or more components. 1. An implementation plan That presents A proposed schedule for the construction and delivery phases 2. A final cost-benefit analysis That determines if the design is still feasible. Given the design specifications and implementations plan you should be able to make much more refined estimates for the remaining costs.
- 9. DESIGN BY PROTOTYPING • Analyst are turning into increasing number to a modern, engineering based approach called prototyping • A prototype according to a dictionary is an original or model on which something is patterned and or a first full scale and usually functional form of a new type or design of a construction. • Engineers build prototypes of engines, machines, automobiles, and the like prior to building actual products. • Prototypes allow them to isolate problems in both requirements and designs.
- 10. PROTOTYPING APPROACH ADVANTAGES • Prototyping encourages and requires active end users participation. This increases end users morale and support for the project. • Interaction and change are a natural consequence of system development that is end users tend to change their mind. It has often been said that end users don’t fully know their requirements until they see implemented. If so prototyping endorses this philosophy. • An approved prototype is working equivalent to a paper design specification with one exception. Errors can be detected much earlier. • Prototyping can increase creativity through quicker user feedback that can lead to better solutions.
- 11. • Prototyping accelerates several phases of the lifecycle, possibly bypassing the programmer. In fact prototyping consolidates parts of phases that normally occur one often the other. These phases includes the following: 1. Definition: Each prototype can change not only the design, but the actual requirements until the end users accept requirements. In many cases requirements can be defined more quickly with this approach. 2. Design: Screen and report layouts can be very quickly changed until end users accept their designs. 3. Construction: The very act of prototyping requires construction also known as programming. The analyst programs if it’s even possible to use that them the prototype.
- 12. PROTOTYPING APPROACH DISADVANTAGES • Prototyping encourages a return to the code implement and repair life cycles that used to determine information systems. • There are numerous design issue snot addressed by the prototyping • Prototyping often leads to premature commitment to a physical design. On other words the selection phase gets shortchanged. • When prototyping the scope and complexity of the system can quickly expand beyond original plans. This can easily get out of control. • Prototyping often suffers from slower performance then their third generation language counterparts.
- 13. PROTOTYPING LANGUAGES AND TOOLS • Building prototypes makes so much sense that you may wonder why we didn’t always do it. • This reason is simple the technology wasn’t available. • Traditional languages like COBOL, FORTRAN, basic, Pascal, and c don’t lend themselves to prototyping. • Prototyping must be developed and modified quickly, neither of which is possible with third generation languages. Simple prototyping tools: Ads/on-line Application factory Datatrive Focus Ideal natural Intellect
- 14. RAPID VERSUS SYSTEM PROTOTYPING: RAPID PROTOTYPING • Rapid prototyping allows you to create and test input designs, output designs, terminal dialogues, and simple procedures. • The technology of rapid prototyping is unique in that it is not built around a complete applications generator or 4gl • And instead of being built around a DBMS, it is built around a computerized data or a project dictionary. • This dictionary may be a part of a case ( computer- assisted systems engineering).
- 15. SYSTEM PROTOTYPING • System prototyping requires the use of a true fourth- generation language applications generator. The only difference is that they are completed via prototyping. The process goes something like this: 1. A prototype databases would be designed, using whatever constraints are imposed by the 4GL/ AG’s underlying databases. 2. The following task could occur in parallel or in any sequence: a) Prototype outputs can be created using the report generator of the 4GL/AG. Reports generator allow new reports to be quickly defined.
- 16. SYSTEM PROTOTYPING b) Prototype inputs can be created and generated using the screen or report generator of the 4GL/ AG. Screens can be changed to form a dialogue. 3. Once the inputs and outputs are completed, they would be integrated around some sort of user friendly shell. The most common shell consists of menus and submenus.
- 17. THANK YOU