The ICT Lounge
Section 8.4:
Stage 3 - Development and Testing
When designs for the new system (stage 2) have been complete, development can begin. Development is stage 3.

A system's developer will follow the designs to produce a working system that meets all requirements.

There are two parts to stage 3.... Development and Testing.
Key Concepts of this section:
Understand what is involved in the development and testing stage.

Know the different stages that are involved during development and testing.

Be able to describe the different stages that are involved during development and testing.

Stage 3a - Development
Key Words:
Development, File Structure, Validation Checks, Data Entry Forms, Output Formats
What is system development?

System development just means to 'build the system'.

A builder will build a house correctly by reading plans provided by an architect.

A system is built in much the same way -- the developer will follow plans provided by systems' analysts and designers.
When stage 1 (analysis) and stage 2 (design) have been completed, there will be clear lists of requirements and sets of designs that a developer can follow in order to create a working system.

If analysis and design have been done properly, the developer should be able to create a system that works fully and is free of errors.

HINT - Think of systems development in the same terms as building a house.

A bricklayer follows instructions (plans) provided by an architect and a system's developer follows instructions provided by a system's analyst and designer.

The architect will include things like wall length, height and shape on a building's plans

The systems analyst/designer will include things like calculations, layout of the input/output screens and how data will be entered in the system plans.

What are the stages of development?
The development stage is broken down into 4 parts:
  1. Creating a file structure to store data
  2. Create validation rules to make sure that data entered is sensible
  3. Create a user-interface to allow data to be entered into the system
  4. Create output formats (reports, payslip's, bills etc)
Creating file structures to store data
Systems (like databases) that are required to hold data need to use file structures.

Most systems are required to hold lots of data. File structures allow this data to be stored in an organised way (click to zoom)
If the system makes use of more than one table, the developer will need to also need to set up key fields in order to link all of the tables together.

This was covered in detail during
Unit 5 - Types of Databases

A system with more than one table is linked together using key fields (the bold text)
File structures determine how the data is stored in the system and are made up of 4 parts:
(each field is assigned a data type)
Field Properties
(field length, decimal places etc)
An example of a file structure can be seen in the image below:
(For more details see Unit 5 - Database Structures)

Test data is entered into the fields to make sure that data is being stored correctly.




Creating Validation Rules / Checks
Validation checks will have been thought about and decided on during the design stage.

A validation rule which will force users to only enter
'F' (for female) or 'M' (for male) .
The validation rule in action. I have tried to
enter 'G' into the gender field and the system
has rejected the data
Validation checks make sure that only correct data can be entered into the system.

For example:
A validation check of Male OR Female set as part of the Gender field in a database system would ensure that the user could not input anything else.

If the user tried to enter anything other than 'Male' / 'Female', the system would flag this up as an error.

Once all of the necessary validation checks have been programmed into the system, they are tested to make sure that they work.

Validation checks are tested in two ways:

1. Entering data that should be accepted
2. Purposefully entering data that should not accepted.

IF the validation check is working, the acceptable data will be entered into the system without problem and the unacceptable data will be rejected.



Creating Input Methods (Data Entry Forms)
User-interfaces have to be created to allow users to input data into the system.

A data entry form.

The data entry form makes use of form controls appropriately.

For example - questions where the answer could be anything (like name) are assigned text boxes.

Questions with limited choices (like type of organisation) are restricted to 4 options
The screens of a system that allow users to enter data into the system are called 'Data entry forms'. Data entry forms should be well designed to make sure that they are easy to use.

A good data entry form should....

* Include entries for all of the required fields
* Make use of form controls appropriately (see below)
* 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

What are form controls?
Form controls are the items on a data entry form that allow you to interact with the system and enter data. Form controls include:

Text boxes
Used to enter text using a keyboard

Option buttons
Used to select from a number of options
(only one option can be selected)

Check boxes
Used to select from a number of options
(more than one option can be selected)
Combo boxes (drop-down lists)
Used to select one item from a list of options
Command buttons
Used to perform a command
(save for example)
Creating Output Formats (reports, invoices, payslip's etc)
Two types of system outputs have to be created:
  • On-screen outputs
  • Printed outputs (hard copies)
Some outputs are designed to be printed
(like this phone bill).
Some outputs are designed to be displayed on-screen (like this online phone bill)..
On-screen outputs can be created with features that cannot be included with printed outputs.

For example - on-screen outputs can make use of animation, hyperlinks, sound, video (multimedia) etc.

Printed outputs are limited to good old text, images, colours and charts etc.
The system developer will create all outputs by following designs provided during stage 2.

The developer will ensure that any hardcopy outputs will be printable by clicking a 'Print' button.

Outputs are tested by checking that the information output is clear, easy to read, complete and correct.

The image below shows a system report being designed:
Stage 3b - Testing
Key Words:


Coming soon......



Next - Integration