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Verification
Verification is checking to make sure that data has
been entered correctly.
Verification is often carried out by getting two users to
enter the same set of data at different computers.
Once both users have entered the data the two sets of
data are compared to check that they match up.
Any data that does not match up is rejected.
Verification can also be carried out by software which
might, for example, ask for the same data to be entered
twice. If both entries don't match up the data is
rejected.…read more

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Validation
Validation checks are carried out by software to make
sure that data which has been entered is allowable and
sensible.
Data that is not sensible or allowed is rejected by the
computer.
There are many different types of validation check that
software can make on data.
We will now look at some of these in more detail.…read more

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Range check
Range checks are used to check that data is within a
certain range of numbers or a specific set of values.
For example if the examination marks for a group of
students was being input a range check could be used to
make sure that each mark was greater than or equal to
zero and less than or equal to the maximum possible
mark.…read more

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Type check
Type checks are used to check that the correct type of
data has been entered in a field.
For example if numeric data is being input a type check
could be used to make sure that text data isn't entered
by accident.
Length check
Length checks are used to check that input data
contains a certain number of characters.
For example if a value in a certain field had to contain
five digits and only four digits were input, an error
message would be given to the user.…read more

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Presence check
A presence check is used to make sure that a value has
actually been entered in a field.
In some database files entering data in certain fields can
be optional. Other fields, such as key fields for example,
are compulsory and must have values entered in them.
A presence check makes sure that data is present in a
field where it is compulsory that a value is needed.…read more

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Comments

Miss Morgan

A great resource to explain data validation and verification.

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