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Validation. Validation is a check that is carried out during the process of data entryIt is also the process by which data is accepted as being sensible and reasonable in the context within which it is being usedValidation is performed by the computer program that is in use, and consists of a seri
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1. AS Level ICT Data entry: Validation
2. Validation Validation is a check that is carried out during the process of data entry
It is also the process by which data is accepted as being sensible and reasonable in the context within which it is being used
Validation is performed by the computer program that is in use, and consists of a series of checks that are called validation checks
3. Validation checks Validation checks are used to restrict the data that can be entered so that it complies with the data rules that have been laid down
There are several different type of validation check that can be used, each of which has specific uses
4. Validation checks These validation checks include:
Data type checks
Presence checks
Length checks
File/Table lookups
Cross field checks
Range checks
5. Validation checks These validation checks include:
Format checks
Check digits
Parity checks
Spell checkers
Grammar checkers
Custom dictionaries
6. Data type checks Character type checks make sure that the correct type of data has been entered
Example:
A letter has been entered into a database field that has been pre-set so that only it will only accept numerical data
The incorrect data type triggers a warning message and will not allow further data to be entered until the error has been corrected
7. Data type checks
8. Presence checks Presence checks ensure that data that must be entered is entered
Example:
An online application form for a job requires the applicant to include their National Insurance number
If that was not entered the presence check would detect this and notify whoever was entering the data
9. Length checks A length check makes sure that the number of characters entered into field matches that fields requirements
Example:
A National Insurance number will have two letters, followed by six numbers, followed by one letter (e.g. YY232425A)
10. Length checks If this data is entered into a field specially set up to only accept data that is nine characters long, a length check will immediately identify if more or less than that number of characters has been entered
11. File/Table lookups A lookup table contains a list of valid codes that can be used to enter data
If a code that is not in the lookup table is entered, it is rejected
This prevents any incorrect data from being processed
12. File/Table lookups Example:
A data management system for a restaurant uses lookup tables that contain the codes for each course that can be ordered
13. File/Table lookups