3.9 techniques and tools for systems development

3.9 Techniques and Tools for Systems Development

1. What investigation techniques could be used in the analysis phase of development?2. What are the benefits of an interview?3. How can you ensure on a successful interview?4. Who is the questionnaire method appropriate for?5. What are the benefits of observation?6. What does ‘document analysis’ involve and what would you look at?7. Explain Joint Application Development (JAD)8. Explain the term ‘Thought Shower’9. Why is it important to record your findings?10. What should you keep a record of during and after your investigations?

11. When analysing the processes that go on in an organisation what diagrams can be used to illustrate this?12. What is SSADM?13. What does an information flow diagram aim to illustrate?14. Draw and label 3 symbols that are used in an information flow diagram.15. Draw an information flow diagram to illustrate a teacher buying books for her class16. What does a system flowchart aim to illustrate?17. Label these symbols:18. Draw a system flowchart to illustrate the processing of cheques at a bank19. What is the purpose of a decision table?20. Create a decision table for the following scenario:

21. What does a data flow diagram illustrate?22. Explain what these symbols show/represent:23. Draw a DFD for this system24. What are the 4 rules of DFD’s?25. What is the purpose of an entity attribute diagram?26. In relation to databases what is an entity? (Give an example)27. What is an attribute? (Give an example)28. In relation to databases what is a relationship? (Give an example)29. What is the purpose of an entity relationship diagram?30. state the 3 types of relationships that can be formed in an entity relationship diagram31. Give examples of each relationship and draw appropriate diagrams to represent them32. If there is a many to many relationship what would you tend to do?

33. What 6 techniques can be used to ensure thorough testing takes place?34. Explain the ‘test harness’ method and identify the benefits of this35. Explain the need and importance of ‘volume testing’36. Explain the need and importance of ‘scalability testing’37. Explain the processes involved with the ‘prototyping’ technique38. Explain ‘Multi-platform testing’ and why it is important39. Explain why ‘simulated environments’ testing is necessary

 Interviews Questionnaires Observation Document analysis Joint Application Development (JAD) Thought showers

 The are a form of open ended discussion Probing questions can be asked Unforeseen questions might stem from conversation Group discussions can be conducted amongst different levels (e.g. strategic, tactical, operational)

 Careful preparation in advance Possibly providing the interviewee with possible questions prior to the interview to allow them to prepare responses Record the conversation (audio/written) so it can be referred back to later on Produce a formal report of the interview and share it with the interviewee(s)

 People in remote locations People whose role is minor but need to be involved Appropriate for a large number of people

 To see first hand how a system is being used To see first hand the ability (or lack of) of the end users To identify what happens when problems occur To observe informal communication e.g. telephone calls

 Studying of business materials e.g. policy documentation, staff handbooks etc. Studying of documents used in a system (data inputs and information outputs) e.g. data collection forms, invoices, receipts This technique allows you to identify the data that needs to be stored, the information that needs to be produced and the format the information needs to take

 Where a group of people get together until a complete set of requirements are documented and agreed. Useful for projects where a number of different users are involved Benefits of this technique is that everyone discussing the requirements together means that they have to come to a joint agreement about what is required

 A collaboration of many people contributing to the solution of a problem via a simple diagram method. Ideas might be extreme, innovative.

 It provides a permanent record Several people may need to work on the same project and need access to the information Findings may need to be checked and confirmed Provides structure and helps analyse

 All formal documents e.g. questionnaire responses, interview reports, minutes of meetings etc. Unstructured findings e.g. facts or opinions give in meetings

 Information Flow Diagram System Flowchart Decision Tables Data Flow Diagrams

 Structured Sytems Analysis and Design Methodology A standard method for analysis and design of large scale applications for the UK government It uses a combination of text and diagrams

 It aims to show how information moves between the parts of an organisation, both internally and externally

Information Flow Internal ExternalDepartment Organisation

Teachers 7 Confirmation of receipt 1 Order Sent 2 Order Confirmed 6 Receipt sentFinance 3 Invoice sent Supplier Office 4 Payment authorised by BACS 5 Confirms PaymentBank

 It illustrates how data and information flows through the system, including manual operations and manipulation of information

Input or Output of data ProcessInteraction Input e.g. bykeyboard, bar code reader Online data storagePrinted output as a singledocument Magnetic disk data storagePrinted output as multipledocuments Magnetic tape data storage

Cheques MICR Validation Customer ccounts Sort Transaction Transaction File File Updated Customer Accounts Statement

 Used to define the logic behind how a decision is made. It is designed to help you make sure that all possibilities are considered and to document all the possible outcomes

 A college will offer a student a place if their interview is satisfactory, their school reference is OK and they have the right GCSE grades. They will be placed on the waiting list if their school reference is OK and their interview is satisfactory or they have the right GCSE grades. Their application will be rejected if their interview is not satisfactory and they do not have the right GCSE grades.

 A college will offer a student a place if their interview is satisfactory, their school reference is OK and they have the right GCSE grades. They will be placed on the waiting list if their school reference is OK and their interview is satisfactory or they have the right GCSE grades. Their application will be rejected if their interview is not satisfactory and they do not have the right GCSE grades.Condition/Cause Value of ConditionSatisfactory interviewSchool reference OKRight GCSE GradesAction/Effect Value of ActionPlace offeredWaiting ListRejected

 A college will offer a student a place if their interview is satisfactory, their school reference is OK and they have the right GCSE grades. They will be placed on the waiting list if their school reference is OK and their interview is satisfactory or they have the right GCSE grades. Their application will be rejected if their interview is not satisfactory and they do not have the right GCSE grades.Condition/Cause Value of ConditionSatisfactory interview Y Y Y Y N N N NSchool reference OK Y Y N N Y N Y NRight GCSE Grades Y N Y N N Y Y NAction/Effect Value of ActionPlace offered XWaiting List X X X XRejected X X X

 They identify where the data comes from, the processes it passes through and where the data goes to.

 Data Source or destination Duplicated Data source or destination Process Data Store

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 1: Identify where data is captured from Customer

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 2: Identify where data is distributed to Customer Support Operator Team

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 2&3: Describe the overall process, map these out in a diagram Customer 0 Hospital Request Support Operator Team

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 4: Link them with data flows that are labelled – Level 0 finished Customer Response Customer Request 0 Support Request Hospital Request Support Operator Details of request Team

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 5: Identify and draw the processes that make Level 0, Allocate descriptions to these 1 2 Receive and log Create a job record Support Request 3 Update Job record

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 6: Layout the data sources and data flows from Level 0 diagram Customer Customer 2 1 Request Receive and log Create a job record Support Request Response Details of Request Operator Support Support Request Request Response 4 Support Team Add/Update Customer Details 3 Update Job record

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 7: Draw in any data stores used in the process Customer Customer Customer 2D1 Requests 1 Request Receive and log Create a job record Support Request Response Details of Request Operator Support Support Request D2 Customer Details Request Response 4 Support Team Add/Update Customer Details 3 D3 Job Record Update Job record

 In a hospital system the user will make a request for support by calling a central number. The operator will take details of the request, create a numbered job record and send it to the appropriate support team who will then respond. The user will be given the job number so that they can track progress if they need to and the support team will update the job record as they deal with the problem.Step 8: Link the new processes and data stores with the named data links Customer Request Customer Customer Request Customer Job number 2D1 Requests 1 Receive and log Create a job record Support Request Support Request Numbered job Operator record Numbered job Customer D2 Customer Details record Details Response New/existing 4 Support customer data Problem Dealt Team Add/Update with Customer Details 3 D3 Job Record Update Job record Problem Dealt with

1. There should be a data store for every entity2. Information flows show data and not physical items3. Entities don’t link directly to data stores4. What goes in must come out

 It shows the relationship between an entity and the attributes that describe it

 Things that have data stored about them Example ◦ Systems concerning a school, entities would be:  Student  Teacher  Courses

 Describes an individual data item within the entity Attributes of a student would be: ◦ Student Surname ◦ Student Forename ◦ DOB

 Describes the link between two entities Example ◦ A student and a member of staff might be linked by the relationship ‘tutor’ ◦ One tutor can tutor many students ◦ One student can only have one tutor

 When building databases it shows how two or more entities are related

1. One to one2. One to many3. Many to many

 One to one Department Has Department Manager One to Many Has Employee Department Many to Many Has Employee Project

 Create a new entity and use this to join the other entities as a one to many relationship Employee role Project

1. Test harnesses2. Volume testing3. Scalability testing4. Prototyping5. Multi-platform testing6. Simulated environments

 Through the use of specialist software and test data this method allows some types of testing to be automated. The software is setup to test the data under specified conditions, comparing actual outputs to expected outputs. Economical benefits with regards to time and money

 Tests that a new system works with large volumes of data. Tests the limits of the software under heavy load

 Tests that a system will perform as required even if the system has to deal with an increased workload e.g. increased users, larger amount of transactions

 Used to gather feedback throughout the development process rather than just at the end You build a limited version of the solution and show it to the client You make changes and then show it again Repeats until the solution meets the clients requirements

 Tests to ensure that the system operates on a variety of hardware specifications and operating systems Must consider mobile devices

 It may not always be feasible to test a system in every environment, so simulated environments are used E.g. ◦ Testing it over the companies WAN may cause disruption so you might simulate this process, change conditions (bandwidth speeds, amount of data transferred etc.) Simulating this would not cause disruption.

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3.9 techniques and tools for systems development

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