5. Design Specification

Now that the users and the analyst have agreed the overall project, it is time to provide details that the development team can use to actually start work.

The design specification document is likely to contain details of the following:

 

Purpose of the system What problem the system is designed to solve
Screen layouts and style templates

Background colour or images

Font style and weights

Label text and other information on screen

Titles, sub titles

Character widths of input boxes

Design features such as margins, borders and shading

These features will usually incorporate the businesses' house style
Data structures The design and layout of the new tables
Inputs The inputs for the new system, e.g. forms, buttons, list boxes, combo boxes
Outputs The outputs from the system e.g. printed outputs, onscreen outputs
Processing The processing that will take place and the hardware necessary to support that processing
Validation rules The validation which needs to be set up to ensure data integrity
Error messages Error messages which will appear if the validation rules are broken or an error occurs in the system
Modelling diagrams Data flow diagrams, entity relationship diagrams and state transition diagrams
Software The software and programming languages to be used to develop the system
Hardware The hardware that will be required to develop the system
Test plan The test plan which will be used during the testing phase to check the system works properly

 

One popular way of explaining to the developer what is required is to produce a mock-up of the screen. This mock-up is produced with the help of an image editing application such as Photoshop or Paintshop Pro.

The design document should be comprehensive enough for the developer to start work. It does not need to explain *how* it is to be done but *what* needs to be done.

 

challenge see if you can find out one extra fact on this topic that we haven't already told you

Click on this link: Design Specification