1. Design Documentation
Software Development
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2. Software Development Lifecycle
This is used by software designers - the whole
design process can be thought of as a cycle
The stages are:
Identify - Define requirements and specification
Design - Plan the solution to the problem
Develop - Produce the program code
Test - Locate and remove any errors
Evaluate - Review against program requirements
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3. Identify the Scope
The first stage of the design process is based upon
analysing the user’s requirements to determine
what is achievable with the resources available.
Resource limitations (called constraints) usually
involve time and money.
Prioritise the most important features and decide
what will be included in the first version of the
software and what can be left out and put on the
‘wish list’ for future versions.
You then need to produce a formal written
requirements specification for the program
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4. Design Documentation
Requirement Specification:
Inputs are required from the user
Outputs expected by the user
Processing needed to provide functionality
Constraints e.g. time, funds, specialist skills
Screen Designs
Program Design: Modules and Algorithms:
Structure Diagram / Flowcharts / Pseudocode
Data Dictionary
Test Plan
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5. Requirements Specification
Inputs: List of all the data that is input by the user
Give specific details of the actual data, e.g. first name
and last name of user
Identify valid and invalid values for text and acceptable
ranges for numeric data
Outputs: List of all output expected by the user
Give specific details of the actual data and format, e.g.
Monthly sales report which will be displayed in a bar
chart, showing total sales for each product
Include any help information e.g. Instructions, error
messages or visual feedback
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6. Requirements Specification
Processing: Give details of all the functions the
program will need to have.
You should break this down into each processing task
e.g. validation, calculations, formatting etc.
Explain what each function should do (not how – yet!)
There could be many of these in your proposed system
Constraints: Identify any resource limitations
It could include budget, development
timescales, hardware available, training
requirements, special needs of users etc.
Give specific details of each, e.g. The total budget
available is £50,000
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7. Screen Designs
Provide a storyboard to show screens at
various stages of the program
Draw them… Count Down
On paper…
In Word or Visio…
In Visual Studio…
They must show
The prompts the user will see
Example input
Example output
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8. Process Specification
Requirements Specification - describes WHAT the
system must be able to do.
Process Specification - provides details of HOW the
required functionality is achieved.
Various techniques used to clarify procedures
Flow Charts
Structure Diagram
Pseudocode / Structured English
Provides the logical design for a computer algorithm
Not language specific
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9. Data Dictionary
This is used to document the variables and data
types used in your program
Show the variable names, datatypes and a
description of what data the variable is going to
store
Identify location e.g. Local or Global
Remember local is better
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10. A Data Dictionary
Table with details of all important variables
Variable DataType Description
VAT Global Single, Constant Holds current VAT
rate (17.5%)
sngVATPrice Local to Single Holds price of goods
Checkout inc VAT
intQuantity Local to Integer Number of items
Checkout
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