INFO 1 C3 - Design of Solutions (Designing the Output (Layout should be…
INFO 1 C3 - Design of Solutions
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
Creates templates used in the design process
Other Design Tools
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 justify the cost of the proposal by offsetting this against the benefits
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
means that the data entered is reasonable or sensible .NOT checking if data is correct
checks if data is in the right format - example the date DD/MM/YYY
Checks if number lies between two given ranges - example 1-100
A check used to check a correct amount of digits have been used - example card number, phone number, bar codes.
Cross field check
A check that looks in not one but two fields - example a gender and title field, Mr and Male accepted Mr and Female not
Hash and control totals
checks for missing records after transmission of data. Hash is the total of non calculable fields
Drop down list
Presents a list of fixed options to choose from - stops irrelevant data from being entered
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
Design of Data Entry
Data is entered into a system through a data capture form - electronic or paper 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
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
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
Designing the Output
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