Validating web source information
For example, many database systems allow the specification of the following l (plus, minus, and parentheses).A more sophisticated data validation routine would check to see the user had entered a valid country code, i.e., that the number of digits entered matched the convention for the country or area specified.A judgement as to whether data is valid is made possible by the validation program, but it cannot ensure complete accuracy.This can only be achieved through the use of all the clerical and computer controls built into the system at the design stage.
It uses routines, often called "validation rules" "validation constraints" or "check routines", that check for correctness, meaningfulness, and security of data that are input to the system.
For example, a US phone number should have 10 digits and no letters or special characters.
Code and cross-reference validation includes tests for data type validation, combined with one or more operations to verify that the user-supplied data is consistent with one or more external rules, requirements, or validity constraints relevant to a particular organization, context or set of underlying assumptions.
For example: Data type validation is customarily carried out on one or more simple data fields.
The simplest kind of data type validation verifies that the individual characters provided through user input are consistent with the expected characters of one or more known primitive data types; as defined in a programming language or data storage and retrieval mechanism as well as the specification of the following primitive data types: 1) integer; 2) float (decimal); or 3) string.