There are many important concepts which we have learnt from our course System Development ovreview. Those cocepts are important due to the following reasons:
System: System is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective. Its main charactersticesc are organization, ineteraction, interdependence, integration and a cenntral objective.
Information System: An IT system is an open system that allows inputs and facilitates interaction with the user. The main charaterstices of an open system are input form outside, processing, output, operating in a cycles through feedback, differentiation and equifinality.
SDLC(System Development Life Cycle): The system has a life cycle, just like a living system or a new product. system analysis and design are keyed to the system life cycle. The analyst must progress from one stage to another methodically, answering key questions and achieving results in each stage.The stages are: a. Recognition of the need for change. b. Feasibility study c. Analysis of the present system. d. Design of a candidate system. e. Testing and implementation of the system. f. Post-Implementation.
The Role of System Analyst: A system analyst is a person who conducts a study, identifies activities and objectives and determines a procedure to achieve the objectives. System analysis has a history dating back to Taylor. Early analysts worked in factories, specializing in improving work methods and setting time standards for production. With the advent of the computers,the analyst assumed the role of a problem solver and a specialist in developing computer applications.
System Planning: Planning information systems has become increasingly important because the information is a vital asset, more and more funds are commited to information systems, and system development is a serious buissness for computers that incorporate data bases and networking. Planning for information systems has a time horizon and a focus dimensions. The time horizon dimensions specifies the time range of the plan, whereas the focus dimensions relates whether the primary concern is a strategic, magerial, or operational. DFD(Data Flow Diagram): The DED flow shows the flow of data, the processes and the areas where thay are stored. It is a commonly used structured tool for displaying the logical aspects of the system under study. Decision tables are used when complex decision logic cannot be represented clearly in a DFD.
Feasibility Analysis: Feasibilty study is carried out to select the best system that meets performance reqirements. This entails idnetification description and evaluation of candidate systems and selection of the best system for the job.Three key considerations are involved in the feasibilty analysis: economic, technical, behavioural.Th various steps involved in the feasibilty analysis are form a project team and appoint a project leader, prepare system flow charts, Enumerate potential candidate systems, describe and identify characterstics of candidate systems, weight system performance and cost data, select the best cnadidat system and prepare and report final project directive to management.
Cost benfit analysis: Cost benefit analysis gives a picture of the various costs, benefits, and rules associated with each alternative system. cost and benifits are classified as tanigible or intengible, direct or indirect, fixed or variable. The procedure entails: a. Identifying the costs and benefits pertaining to a project. b. Caegorizing the various costs and benefits for analysis. c. Selecting a method of evaluation. d. Interpreting the results of the analysis. e. Taking action. System Design: The design focuses on the detailed implementation of the system recommended in the feasibilty study. Emphasis is on translating performance specifcations. The design phase is a transition from a user-oriented document (system proposal) to document oriented to the programmers or data base personnel. It goes through logical and physical design emphasis on the following: a. Prparing input/output specifications. b. Preparing security and control specifications. c. Specifying the implementation plan. d. Preparing a logical design walkthrough before implementations.
Structured Design: Structured design is a data-flow-based methodology that identifies inputs and outputs and describes the functional aspects of the system. It partitions a program into hierarchy of modules organized in a top-down manner with the details at the bottom.
File Organization and Databse Design: The file hierarchy begins with bytes which make up the data items. Data items are record that are grouped to make up a file. Two or more files are database.There are four methods of organizing files: Squential Organization means storing records in contagious blocks according to a key. Indexed- Sequential organization stores records sequentially but uses an index to locate records. Records are related through chaining using pointers. Inverted Lists organization uses an index for each key type. Records are not necessarily in particular sequence. Direct-Access organization has records placed randomly throughout file. Records are updated directly and independently of other records.
DBMS(Data Base Management System): It manages and controls the data base file and handles requests from the application program in a data manipulation Language. To produce the user’s view, the data model represents data structures and describes the view in a data definition language. DDL simply tells the DBMS how the data must be structured to meet the application program requirements. DML, then manipulates the data, DDL describes and identifies data structures, and the DBMS manages and co-ordinates data according to DML requests and DDL descriptions.
System Testing and Quality Assurance: Inadeqate testing or nontesting leads to errors that may be costly when they appear months later. Effective testing translates into cost saving from reduced errors. It also has utility as user-oriented vehicle before implementation. A candidate system is subject to a variety of tests: online response, volume, stress, recovery and security, and usability tests. Each test has a unique benefit for a successful installation. The main purpose of system testing is to identify and correct errors in the candidate system. The performance criteria include: a. Turnaround time. b. Backup. c. File protection. d. The human factor with a focus on ergonomics.
Quality Assurance specialists use three levels of quality assurance: a. Testing a system to eliminate errors. b. Validation to check the quality of software in both the stimulated and live environemnts. c. Certification that the program or software packages is correct and conforms to standards.
Implementation and Software Maintenance: A crucial phase in the systems life cycle is the successful implementation of the new system design. Implementation simply means converting a new system design into operation. This involves creating a new system design into operation. This involves crating computer-compatible files, training the operating staff and installing hardware, terminals and telecommunication network before the system is up and running. In system implementation user training is crucial for minimizing resistance to change and giving the new system a chance to prove its worth.
Security, Disaster/Recovery, and ethics in System Development: Every candidate system must provide built in features for security and integrity of data. ithout safeguards against unauthorised access, fraud, embezzlemnt, fire and natural disasters, a system could be so vulenerable as to threaten the survival of the organization. The strength behind the system integrity and success is ethics and professional standards of behaviour.
The concepts causing the problem: Though our lecturer has tried his best to solve our queries regarding the problem of course but still I feel some problem in undersatnding normalization. Normalization is a process of refining the data structures. Datas are grouped together in the simplestw way possible so that later changes can be made within a minimum of impact on the data structure. When too many attributes are grouped together to form entities, some attributes are found to be entities themselves. Furhter normalization of these entities into atributes linked by common data elements to form relationships improves the effectiveness of DBMS. I felt difficulty in normalizing the tables. I got confused with secondary keys and foreign keys.
The best way to solve this problem is exercise. I will practice with many problems regarding normalization and try to solve them. More I will do practice more it will become easy for me to understand the base of the noramalization and its inner concepts. In the lecture slides our lecturer has given many problems regrading the normalization and this gives me opportunity to dealt with them and to have deep understanding of the normalization and thus able to undertand it completely.
The chart is dvided into main and sub tasks to perform each week. It helps me in submitting assignments and blog questions in time. It helps in managing time in better way. Exam prepartion will be better as the course is devided into sub tasks and a lot of time is give for revision of course.The gantt chart is a great tool of project sheduling. This assignment gives me a chance to use it for scheduling my system development overview course. Due to this I got an opportunity to some extent to know how an Analyst Schedule a project project .