AQA As ICT - 3.3 Data Validation

When you choose a new password and have to enter it twice, it is considered verification. Verification involves comparing two sets of data to check if they match. In this case, the entered password is compared with the re-entered password to ensure that they are the same. This process helps to confirm that the password has been entered correctly and reduces the chances of making a mistake while typing it.

Validation and verification are not the same and do not work the same way. Verification is the process of evaluating a system or component to determine whether it meets the specified requirements, while validation is the process of evaluating a system or component during or at the end of the development process to determine whether it satisfies the specified requirements. In other words, verification checks if the system is built correctly, while validation checks if the right system is built. Therefore, the statement that validation is the same as verification is false.

Data validation is more likely to be found in forms. Forms are used to collect data from users, and data validation ensures that the entered data meets certain criteria or constraints. This helps in maintaining data integrity and accuracy. Word processing software may have some basic data validation features, but forms are specifically designed to handle data input and validation. Therefore, data validation is more commonly associated with forms rather than word processing software.

When you enter data with lots of mistakes or errors, it is called GIGO. GIGO stands for "Garbage In, Garbage Out." This means that if incorrect or faulty data is inputted into a system or process, the output or results will also be incorrect or faulty. In other words, the quality of the output is determined by the quality of the input.

Data validation refers to the process of checking the accuracy, consistency, and reliability of data during its entry into a system. It involves verifying that the data meets certain criteria or rules set by the program. By performing these checks during data entry, errors and inconsistencies can be identified and corrected in real-time, ensuring that only valid and reliable data is stored in the system. This helps in maintaining data integrity and improving the overall quality of the data.

Validation aims to make sure that data is sensible, reasonable, and within acceptable limits. It checks whether the data meets the specified criteria or rules, ensuring that it is allowable within the defined constraints. The process of validation helps to eliminate errors, inconsistencies, and inaccuracies in the data, ensuring its reliability and usability. Therefore, the term "allowable" aligns with the purpose of validation, making it the correct answer.

A picture check would be the most appropriate validation check for a field like postcode, which is always laid out in the same order. A picture check validates the field against a specific pattern or format. In the case of a postcode, it can be validated against a predefined pattern such as a specific number of digits or a combination of letters and digits. This ensures that the postcode entered by the user follows the expected format, reducing errors and ensuring data consistency.

Validation checks are used to ensure that data entered into a system meets certain criteria. Cross Field Check, Character Check, and Presence Check are all examples of validation checks.

Cross Field Check involves comparing the values of two or more fields to ensure they are consistent with each other.

Character Check involves verifying that the data entered contains only valid characters, such as letters or numbers, and does not contain any invalid characters or symbols.

Presence Check ensures that a required field is not left blank or empty.

These checks help to ensure the accuracy and integrity of the data being entered into the system.