Does the system work as expected?

You have learnt about the stages involved in Analysis Design

So what comes next... Creating the system Testing the system Improving the system

Each time that testing shows a problem there will need to be further... Analysis Development Testing

This cycle can happen many times until the system is perfect

Once designed by the systems analyst these must be created by the programmer

The programmer will follow the system analysts designs. E.g Using the recommended programming

language Using the recommended software

Some businesses are able to use existing software to create their desired result Access and Word for example could be used

to mail letters to clients

Other businesses have to have a programme specially written for them this is know as: Purpose built - OR - Bespoke

The systems analyst will have created a test plan.

They will also have prepared a set of test data together with a list of expected resultsTest Test

DataExpected results

Actual results

Comments

Test student D.O.B in school

database

16/04/1992 Accepted

09/09/2007 Accepted

99/99/9999 Rejected

Usually three types of data are tested Normal – data which should be acceptable

or valid in the system.

Extreme – only used when a range of data is used. Extremes of the range are tested.

Abnormal – Data which is not acceptable or valid in the system.

Lets look back at the data on the previous slide – which is which?

Copy the test plan table and try to come up with some more tests that you’d recommend a school tried on their new system.

Test Type of

data

Test Data

Expected

results

Actual results

Comments

Test student D.O.B

in school

database

Normal 16/04/1992

Accepted

Extreme 09/09/2007

Accepted

Abnormal

99/99/9999

Rejected

Data which is already used by the business can be used to test the system.

The data output from the new and old systems should match.

If there are differences then there is a problem to be found and solved.

After the test plan has been fully tested the systems analyst will have to check the results

Are there any problems which need to be solved?

Sometimes single stepping is used. This is when a system can be run just one step at a time until the problem is found

Introducing the system to the place it will be used

Once the system is ready there are 4 main ways of implementing it. Parallel running Direct changeover Phased implementation Pilot running

Switch off the old system and switch on the new.

Simplest scenario Old systems switched off, new

system takes over completely Non critical systems only the new system replaces the

old system in one go saves money in wages/very

fast method of implementation

BUT if anything goes wrong you

don’t have the old system to fall back on

Cannot go back to old system if any problems

Both old and new systems run side by side till new system is working properly

Necessary in critical situations If the new system breaks

down you still have the old system as a backup

BUT It can be a slow process/all

tasks have to be performed twice

Expensive in terms of resources (may need two sets of staff)

New system is brought in one section at a time

Can ensure each part of new system works properly before changing the next part

Eg new library systemBUT Takes longer than

direct changeover If new system

unsuccessful, may lose some data

Eg in large banks or corporations

One branch changes to new system, identifies any problems

Other branches function as normal

Problems can be identified & solved before new system is rolled out to all branches

BUT If new system

unsuccessful, may lose some data

Direct changeoverThe old system is scrapped and immediately

replaced by the new system. With this option there is a danger that there may still be problems with the new system. Even though it is the most risky type of changeover, many companies use this method.

Phased changeoverThe change over is split into phases or stages.

Each stage is introduced one at a time and the old system is kept running to do the remainder of the tasks that have not yet been changed.

Parallel runningRunning both the old and new system until you are

certain the new system is working correctly. Parallel running is likely to be the most expensive as it involves doing the work twice for a period of time. However, it is the safest. If there are any bugs in the new system, you can always go back to the old system while the problems are corrected.

Pilot changeoverChanging over in a small part of the company to start

with. Only when the system is deemed satisfactory will it be rolled out to the rest of the organisation. A supermarket introducing a new 'self-scanning' system might choose to introduce it in two or three stores at first. This is a pilot changeover.

The analyst can not stay with the business for ever – a guide to help the new users

Systems usually have two types of documentation Technical documentation User documentation

User manual Technical manualThe purpose of the program The purpose of the program

Loading and running the program

Hardware and software requirements

How to use the program: entering data, saving, editing, sorting, printing...

Limitations of the program

Input and output formats File structures

Hardware and software requirements

Program coding

Limitations of the program Variables

Error messages Dataflow diagrams

Troubleshooting Validation routines

Frequently asked questionsProgram and system flowcharts