3.9 techniques and tools for systems development

INFO 33.9 Techniques and Tools for Systems

Development

Specification

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?

To consolidate you should be able to answer these questions…

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 bank

19. 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 this

35. 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

9.1 What investigation techniques could be used in the analysis phase of development?

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)

9.2 What are the benefits of an interview?

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)

9.3 How can you ensure on a successful interview?

People in remote locations

People whose role is minor but need to be involved

Appropriate for a large number of people

9.4 Who is the questionnaire method appropriate for?

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

9.5 What are the benefits of observation?

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

9.6 What does ‘document analysis’ involve and what would you look at?

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

9.7 Explain Joint Application Development (JAD)

A collaboration of many people contributing to the solution of a problem via a simple diagram method.

Ideas might be extreme, innovative.

9.8 Explain the term ‘Thought Shower’

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

9.9 Why is it important to record your findings?

All formal documents e.g. questionnaire responses, interview reports, minutes of meetings etc.

Unstructured findings e.g. facts or opinions give in meetings

9.10 What should you keep a record of during and after your investigations?

Information Flow Diagram System Flowchart Decision Tables Data Flow Diagrams

9.11 When analysing the processes that go on in an organisation what diagrams can be used to illustrate this?

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

9.12 What is SSADM?

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

9.13 What does an information flow diagram aim to illustrate?

9.14 Draw and label 3 symbols that are used in an information flow diagram.

Internal Department

External Organisation

Information Flow

9.15 Draw an information flow diagram to illustrate a teacher buying books for her class

Teachers

Finance Office

Supplier

Bank

3 Invoice sent

2 Order Confirmed1 Order Sent

7 Confirmation of receipt

4 Payment authorised by BACS

5 Confirms Payment

6 Receipt sent

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

9.16 What does a system flowchart aim to illustrate?

9.17 Label these symbols:

Input or Output of data

Interaction Input e.g. by keyboard, bar code reader

Printed output as a single document

Printed output as multiple documents

Process

Online data storage

Magnetic disk data storage

Magnetic tape data storage

9.18 Draw a system flowchart to illustrate the processing of cheques at a bank

MICR Validation

Transaction File

Sort Transaction

File

Customerccounts

Updated Customer Accounts

Cheques

Statement

9.19 What is the purpose of a decision table?

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.

9.20 Create a decision table for the following scenario:



Condition/Cause

Value of Condition

Satisfactory interview

School reference OK

Right GCSE Grades

Action/Effect Value of Action

Place offered

Waiting List

Rejected



Condition/Cause

Value of Condition

Satisfactory 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 N

Action/Effect Value of Action

Place offered X

Waiting List X X X X

Rejected X X X

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

9.21 What does a data flow diagram illustrate?

Data Source or destination

Duplicated Data source or destination

Process

Data Store

9.22 Explain what these symbols show/represent:

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.

9.23 Draw a DFD for this system

Customer

Step 1: Identify where data is captured from



Customer

Step 2: Identify where data is distributed to

Support Team

Operator



Customer

Step 2&3: Describe the overall process, map these out in a diagram

Support Team

Operator

Hospital Request

0



Customer

Step 4: Link them with data flows that are labelled – Level 0 finished

Support Team

Operator

Hospital Request

0

Customer Request

Details of request

Support Request

Response



Step 5: Identify and draw the processes that make Level 0, Allocate descriptions to these

Receive and log Support Request

1

Create a job record

2

Update Job record

3



Step 6: Layout the data sources and data flows from Level 0 diagram


1Create a job record

2

Update Job record

3

Customer

Support Team

Operator

Customer Request

Details ofRequest

Response

Response

SupportRequest

SupportRequest

Add/Update Customer Details

4



Step 7: Draw in any data stores used in the process



2

Update Job record

3

Customer

Support Team

Operator

Customer Request

Details ofRequest

Response

Response

SupportRequest

SupportRequest

Job RecordD3

Customer DetailsD2


4

Customer RequestsD1



Step 8: Link the new processes and data stores with the named data links



2

Update Job record

3

Customer

Support Team

Operator

Customer Request

Problem Dealt with

Numbered job record Numbered job

record

Job number

SupportRequest

Response

Job RecordD3

Customer DetailsD2

Problem Dealt with

Customer Details


4New/existing customer data

Customer RequestsD1

Customer Request

1. There should be a data store for every entity

2. Information flows show data and not physical items

3. Entities don’t link directly to data stores4. What goes in must come out

9.24 What are the 4 rules for DFD’s?

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

9.25 What is the purpose of an entity attribute diagram?

Things that have data stored about them

Example◦ Systems concerning a school, entities would be:

Student Teacher Courses

9.26 In relation to databases what is an entity? (Give an example)

Describes an individual data item within the entity

Attributes of a student would be:◦ Student Surname◦ Student Forename◦ DOB

9.27 What is an attribute? (Give an example)

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

9.28 In relation to databases what is a relationship? (Give an example)

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

9.29 What is the purpose of an entity relationship diagram?

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

9.30 state the 3 types of relationships that can be formed in an entity relationship diagram

One to one

One to Many

Many to Many

9.31 Give examples of each relationship and draw appropriate diagrams to represent them

Department Manager

Department

Employee Department

Has

Has

Employee ProjectHas

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

9.32 If there is a many to many relationship what would you tend to do?

Employee Projectrole

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

9.33 What 6 techniques can be used to ensure thorough testing takes place?

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

9.34 Explain the ‘test harness’ method and identify the benefits of this

Tests that a new system works with large volumes of data.

Tests the limits of the software under heavy load

9.35 Explain the need and importance of ‘volume testing’

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

9.36 Explain the need and importance of ‘scalability testing’

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

9.37 Explain the processes involved with the ‘prototyping’ technique

Tests to ensure that the system operates on a variety of hardware specifications and operating systems

Must consider mobile devices

9.38 Explain ‘Multi-platform testing’ and why it is important

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.

9.39 Explain why ‘simulated environments’ testing is necessary

3.9 techniques and tools for systems development

Education