Data Validation and Verification

Data Validation

Data validation is a process that checks whether the data entered into a system follows the specified format and is sensible, accurate and meaningful.
Range check is a type of data validation that confirms whether the data falls within a predetermined upper and lower limit. For instance, a percentage must be between 0 and 100.
Type check is a form of data validation that ensures the entered data is the correct type. For example, a phone number field should only contain numeric characters.
Length check ensures that the entered data is of the appropriate length. For instance, a National Insurance number must be composed of two letters, six numbers, and one letter.
Format check involves verifying if the data entered adheres to a specific pattern. For example, a postcode must consist of two parts separated by a space.
A presence check ensures that key fields are filled in and are not left blank. For example, an email field in an account sign-up form must not be empty.
Lookup check is where the entered data is cross-referenced with a set of known values in a database or a list. For example, this check can verify that a user-entered product code exists in the product database.

Data Verification

Data verification is a process aimed at verifying if the data that was input is an exact match to the original source.
An example of data verification is double-entry, where data is input into the system twice, and the two inputs are compared for discrepancies.
Parity check is a data verification method often used in telecommunications and data transmission. It involves adding an extra parity bit to each byte of data to help detect errors in transmission.
Check digit is another data verification method. It is a form of redundancy check used for error detection on identifiers such as credit card numbers. A computed “check digit” is appended at the end of a number to corroborate its validity with a mathematical algorithm.
Checksum is a count of the number of bits in a transmission unit that is appended to the data for error detection. If the calculated checksum doesn’t match the appended checksum, it’s a clear indicator of an error during transmission.