INFO 1 C3 - Design of Solutions

Standards

When working as a team it is important to use standards; If someone is ill the other workers can cover the absence

Standards are agreed nationally and all developers will be working on the same standards.

A widely used one is Structured Systems Analysis and Design Methodology (SSADM). It is a structured methodology that provides a set approach to information systems dev.

Specifies stages and tasks which have to be carried out, what needs to be produced and techniques used in production

SSADM has 3 Techniques

  • Logical Data Modelling
  • Data Flow Modelling
  • Event Modelling
    Creates templates used in the design process

Other Design Tools

Gantt Charts

SWOT analysis

Cost-benefit analysis

Impact Analysis

is used to justify the cost of the proposal by offsetting this against the benefits

Most popular tool. A diagrammatic overview of the timing of the project. Shows clearly how project should progress; predicts start and ends of tasks

is used to examine the strengths and weaknesses, opportunities and threats of a given project. S & W are examined from internal view and O&T from external view. For proposal to be viable, S outweigh W and O outweigh T.

is used to examine the impact of a proposal on the system's environment. Each impact is given pos and neg value. Fully analysed pos should outweigh neg.

Validation and Verification

Validation

Verification

means that the data entered is reasonable or sensible .NOT checking if data is correct

means that the data entered matches the original source data

Ways of verifying data

Re-entering or re-reading data input - example of re-entering data is a password check

Example: checking a backup of a system has been carried out correctly by backing up again and checking against the original backup

Re-reading data could be carried out in a an online transaction as there is a OK button at the bottom of the page - assumed that customer will check before proceeding . Details checkied against the card details

Format Check

checks if data is in the right format - example the date DD/MM/YYY

Range Check

Checks if number lies between two given ranges - example 1-100

Check digit

Cross field check

Hash and control totals

Drop down list

A check used to check a correct amount of digits have been used - example card number, phone number, bar codes.

A check that looks in not one but two fields - example a gender and title field, Mr and Male accepted Mr and Female not

checks for missing records after transmission of data. Hash is the total of non calculable fields

Presents a list of fixed options to choose from - stops irrelevant data from being entered

Design of Data Entry

Data is entered into a system through a data capture form - electronic or paper based

Computer based

  • allows for checking of the data as it is typed - data is rejected if it does not meet the parametres
  • Larger volumes are entered more quickly and efficiently - same for smaller batches
  • A computer is needed

Paper Based

  • Allows data entry anywhere
  • However this data will still be inputted to a computer either manually or a scanner
  • Increased chance of computer error when copying data

Designing a computer-based data entry form

Inclusion of drop down boxes and any validation rules

Positioning of data entry boxes to provide user-friendly interface and a logical layout to the system

Valifation checks should be notes

Easier and more proffessional to produce on paper than using a computer

Designing User Interfaces

Way data is entered to the system - keyboard, mouse?

Accessibility of the system - disabled need voice output or voice input - for visually and the physically impaired

Screen display - what is going to be on it? Images? What Images?

House colours or style

logical in its use to reduce the amount of key and mouse presses - simple to use and builds on skills from other interfaces

Designing the processes

Sorting data, calculations, any searches - all are processes

Designing the Output

How?

  • write briefly about what the process is doing - not jargon
  • look to see if it does what supposed to do
  • Make nessicary changes
  • Doc original and changes made - forms a project log
  • What fields are going to be in each of the tables?
  • What fields are going to link each of these tables together? Primary and secondary keys?
  • Taking each field in turn we need to design the data type and the format or the number of charcters.
  • Again taking each field we need to look at validation checks should be used or not

The process is not the clicking of a button it is what the button does

Layout should be similar to current documents; this is to keep continuity

info stored must be what the user wants

Info should be organised sensibly and match what is required

Printouts look professional and consistent feel to them

Look good in black and white as well as colour

Sits sensibly on the page

Must work on the clients computer specs