Data validation means exactly what it sounds like, your program checks the data to make sure it meets some rules or restrictions. Validation and verification are two ways to check that the data entered into a computer is correct, because data entered incorrectly is of little use. There are many different data validation checks that can be done.
Data validation is a vital part of any application, as it guarantees that a system works on clean, perfect and helpful data. for instance, you might need to ensure that passwords are no less than eight characters in length, or guarantee that usernames are unique. Characterizing acceptance rules makes structure taking care of much, much less demanding. Take Umuzi for instance, when people apply to Umuzi they sometimes provide invalid data. i.e, invalid ID numbers and cellphone numbers. Often we just need to make sure that whatever information is provided is in the right shape.
Validation is important for a lot of reasons. One big reason is that a lot of data comes from people. People make mistakes, and not everyone is data literate or even computer literate enough to consistently create good data. Data capturers make mistakes, people mess up when filling in forms, people do strange things when interacting with websites and apps.
Sometimes computers make invalid data. This could be due to software errors or even hardware faults.
There are a number of validation types that can be used to check the data that is being entered.
| Validation type | How it works | Example usage | ||
|---|---|---|---|---|
| Check digit | The last one or two digits in a code are used to check the other digits are correct | Bar code readers in supermarkets use check digits | ||
| Format check | Checks the data is in the right format | A National Insurance number is in the form LL 99 99 99 L where L is any letter and 9 is any number. | ||
| Length check | Checks the data isn’t too short or too long | A password which needs to be six letters long | ||
| Lookup table | Looks up acceptable values in a table | There are only seven possible days of the week | ||
| Range check | Checks that a value falls within the specified range | Number of hours worked must be less than 50 and more than 0 | ||
| Spell check | Looks up words in a dictionary | When word processing | ||
| Presence check | Checks that data has been entered into a field | In most databases a key field cannot be left blank |
We check the data to make sure that the user did not make a mistake, accidentally or intentionally, which can prevent our program from functioning correctly or corrupt the data as this has security and data integrity implications.
Data Verification is a process that is performed to check data for accuracy and inconsistencies after the process of selecting, preparing, extracting, and transforming data either from a direct user or another process.
There might be more methods of data verification in the world, these are the two most common methods of data verification:
Double entry - entering the data twice and comparing the two copies. This effectively doubles the workload, and as most people are paid by the hour, it costs more too.
Proofreading data - this method involves someone checking the data entered against the original document. This is also time-consuming and costly.
If you are familiar with any other methods of data verification, Feel free to contribute.