L11 - L12 FAG1003 Systems Cycles; Part 1.pdf

FAG1003 Information and Communication Technology The Systems Life Cycle Systems Analysis and Design RaihanZ  What is the purpose of systems analysis and design?...

FAG1003 Information and Communication Technology The Systems Life Cycle Systems Analysis and Design RaihanZ  What is the purpose of systems analysis and design? Designing a new system that can P per-B sed Systems carry out the same task better. Having a proper planning or design to avoid serious faults and defects. Computer-B sed Systems a a a  1 ANALYSIS 6 2 EVALUATION DESIGN 5 3 DOCUMENTATION DEVELOPMENT/ TESTING 4 IMPLEMENTATION 1 ANALYSIS What is analysis? What does analysis involve? How is this data obtained? 1 ANALYSIS What is analysis? Current Better New System System Looked at in detail No Current New System System Look at the requirements 1 ANALYSIS What is analysis? What does analysis involve? How is this data obtained? 1 ANALYSIS What does analysis involve? Collecting data about the current Identify inputs, processing and outputs of 1 system / proposed system 4 the current / proposed system Find out problems with the current Identify the requirements of the new 2 system 5 system Establish the problem that the customer 3 needs solving 6 Producing a cost-bene t analysis fi 1 ANALYSIS What is analysis? What does analysis involve? How is this data obtained? 1 ANALYSIS How is this data obtained? Observing people using the current 1 Questionnaires 3 system Looking at the current system’s 2 Interviews 4 documentation 1 ANALYSIS How is this data obtained? 1 Questionnaires ADVANTAGES DISADVANTAGES People often do not complete or return the Questions can be answered quickly questionnaire Answers are more honest as the questions can Unclear questions cannot be explained as be answered anonymously people are left to answer the question alone You may get incorrect data if people have Fairly cheap method of gathering data misunderstood a question Answers to the questionnaires can be analysed It is hard to ask very technical or speci c automatically questions on a questionnaire fi 1 ANALYSIS How is this data obtained? 2 Interviews ADVANTAGES DISADVANTAGES Questions can be explained if they are Interviews take far longer to complete than misunderstood questionnaires. Could be expensive to carry out as the person More complex questions can be asked which being interviewed needs to be taken away will give more detailed ndings from their work. Questions can be changed to suit who is Answers may not be honest as the person being interviewed being interviewed cannot remain anonymous You will get a full set of data as the person being interviewed has no choice but to answer all questions. fi 1 ANALYSIS Observing people using the current How is this data obtained? 3 system ADVANTAGES DISADVANTAGES Person being watched might feel Analyst can see exactly what the current uncomfortable and work in a different way to system does well and not so well usual Not expensive to carry out as the employee is not taken away from their work 1 ANALYSIS Looking at the current system’s How is this data obtained? 4 documentation ADVANTAGES DISADVANTAGES Could save time as there may be copies of Very time consuming to look through all of previous analysis the existing documents Can see existing inputs, processing and Very expensive as the analyst will need to be outputs paid for time spent looking at documentation Allows the analyst to predict the size of the Time could be wasted if existing system needed by looking at the amount of documentation is not relevant to the new data that it will be required to handle system  1 ANALYSIS 6 2 EVALUATION DESIGN 5 3 DOCUMENTATION DEVELOPMENT/ TESTING 4 IMPLEMENTATION 2 DESIGN What is system design? What is included within these designs? 2 DESIGN What is system design? Clear list of How it will look and requirements work Design (plan) Aim: to reduce faults/errors at a later stage 2 DESIGN What is included within these designs? 1 Designing data entry screens 4 Designing screen-based outputs 2 Designing user-interface layouts 5 Designing structures to store data 3 Designing printed outputs 6 Designing data validation methods 7 Designing data veri cation methods fi  1 ANALYSIS 6 2 EVALUATION DESIGN 5 3 DOCUMENTATION DEVELOPMENT/ TESTING 4 IMPLEMENTATION 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage TESTING Stage 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage 1 Analysis System’s Analyst 2 Design Develop the system System’s Designer 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage Create a user-interface to allow data 1 Create a le structure to store data 3 to be input into the system Create output formats (reports, 2 Create validation rules 4 payslip’s, bills etc) fi 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage 1 Create a le structure to store data File structures determine how the is stored in the system and are made up of 4 parts: Tables Fields Data type Unit, decimal Field Properties places Records fi 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage 2 Create validation rules Validation checks have been decided on the To make sure that only correct data design stage can be entered into the system Once all the necessary validation checks Two ways: have been programmed into the system, Entering data that should be accepted they are tested to make sure that they Purposefully entering data that work should not accepted  Example: 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage Create a user-interface to allow data 3 to be input into the system User-interfaces have to be created to allow users to input data into the system The screens of a system that allow users to enter data into the system are called ‘Data entry forms” 3 DEVELOPMENT/ Form controls: the items on a data entry form that allow you to TESTING interact with the system and enter data. Form controls include: DEVELOPMENT Stage Create a user-interface to allow data 3 to be input into the system A good data entry form should… Include entries for all of the required elds Make use of form controls appropriately Include instructions which tell the user how to enter data correctly Make sure that text boxes are large enough to enter the required data Be well designed and easy to understand fi 3 DEVELOPMENT/ TESTING DEVELOPMENT Stage Create output formats (reports, 4 payslip’s, bills etc) Two types of system outputs: On-screen outputs Printed outputs Outputs need to be tested! 3 DEVELOPMENT/ TESTING TESTING Stage 1 Testing individual parts 2 Testing the whole system 3 Type of Test DEVELOPMENT/ TESTING TESTING Stage 1 Testing individual parts It is known as UNIT TESTING Test Plan A good test plan should include… A list of the tests that are to be performed The data to be used in the test The type of test The expected outcome of the test The actual outcome of the test should be logged 3 DEVELOPMENT/ TESTING TESTING Stage 2 Testing the whole system It is known as INTEGRATION TESTING Integrated systems testing is where the system is tested as a whole, across the entire organisation Any problems found during whole system testing will be corrected and re-tested  1 ANALYSIS 6 2 EVALUATION DESIGN 5 3 DOCUMENTATION DEVELOPMENT/ TESTING 4 IMPLEMENTATION