Validation?
Check if data reasonable
Presence check?
Prevent further progress
If req field blank
Format check?
Ensure data matches specific pattern
(dd/mm/yyyy)
Length check?
Ensure data is sensible length
(Name being 3-16 chars long)
Type check?
Ensure data particular data type
(Quantity being an integer)
Range check?
Ensure data within specified range
(Overtime hrs being >0 and <15