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Slide 1

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AS ICT OCR, chapter 1…read more

Slide 2

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Validation definition
Making sure that data is:
· Sensible
· Reasonable
· Complete
· Within acceptable boundaries
Reduces the amount of errors made when data is
entered into a system…read more

Slide 3

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Range check, presence check
Range check
· Data must be a value that falls between two predefined
· Used when data consists of numbers, currency or
· E.g. Shoe sizes in stock has to be between 4 and 9
Presence check
· Requires that a value must be entered
· Makes sure important data isn't missed out, if it is an
error message will appear
· E.g. A school always needs to know a child's emergency
phone number…read more

Slide 4

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Format check, data type
Format check
· Data must conform to a specific layout such as
numbers or letters
· Used when data always consists of the same pattern
· E.g. Postcodes always have the same pattern of: LLNN
Data type
· The data must be a specific type such as text,
boolean etc.
· E.g. Data entered for number of stock must be a
number…read more

Slide 5

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Fixed value, check digit
Fixed value
· Data must conform to one of the fields in a
predefined list
· E.g. In a gender field you can be either male or
Check digit
· Checks errors in long numbers such as ISBN numbers
· Works by producing a number from a mathematical
number based on the check digit and if the same
number isn't calculated as the check digit then an
error message will appear…read more


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