Explain data validation and the various types of validity checks.

Question

What will be an ideal response?

Answer 1

Student responses will vary, but should be drawn from the following information from the text.?Validation is the process of comparing data with a set of rules or values to determine if the data meets certain criteria. Many programs perform a validity check that analyzes data, either as you enter the data or after you enter it, to help ensure that it is valid. For instance, when an admissions department specialist adds or modifies data in a student record, the DBMS tests the entered data to verify it meets certain criteria.?If the data fails a validity check, the computer either should not allow the invalid data to be entered, or it should display an error message that instructs the user to enter the data again. Validity checks, sometimes called validation rules, reduce data entry errors and thus enhance the data's integrity.?Alphabetic/Numeric Check: An alphabetic check ensures that users enter only alphabetic data into a field. A numeric check ensures that users enter only numeric data into a field. For example, data in a First Name field should contain only characters from the alphabet. Data in a Current Enrollment field should contain integers.?Range Check: A range check determines whether a number is within a specified range. Assume the lowest per credit hour fee at the school is $75.00 and the highest is $370.75. A range check for the Credit Hour Fee field ensures it is a value between $75.00 and $370.75.?Consistency Check: A consistency check tests the data in two or more associated fields to ensure that the relationship is logical and their data is in the correct format. For example, the value in a Date Admitted field cannot occur earlier in time than a value in a Birth Date field.?Completeness Check: A completeness check verifies that a required field contains data. For example, some fields cannot be left blank; others require a minimum number of characters. One completeness check can ensure that data exists in a Last Name field. Another can ensure that a day, month, and year are included in a Birth Date field.?Check Digit: A check digit is a number(s) or character(s) that is appended to or inserted in a primary key value. A check digit often confirms the accuracy of a primary key value. Bank account, credit card, and other identification numbers often include one or more check digits.