Which Validation Check Catches It?

About this interactive

One way to keep a database accurate is to check data before it gets in. The lesson walked through the checks a form can make as someone fills it in, and this activity asks you to name which one is doing the work. A mandatory field cannot be left blank; forms usually mark them with an asterisk. An input mask or format check controls how an entry is written: two letters for a state, an @ sign and a proper domain in an email, a set number of digits in a phone number or zip code. A range or limit keeps a value within bounds: a dollar amount that must be positive, a date that must fall in a sensible window, or a maximum number of records someone can enter at once. A data type says what kind of value a field holds. An integer is a whole number with nothing after a decimal point; a decimal can have one; a string is a run of characters, letters and numbers alike. A field set to integer rejects 2.5 not because of its format but because it is not a whole number. A check digit is a digit worked out from the other digits in the number. An ISBN, the number given to every published book, carries one at the end: the first nine digits are put through a calculation and the result is the tenth. If someone mistypes a digit, the calculation no longer matches the last digit, and the database knows the number was entered wrong. The pair most often confused is format and data type. Ask whether the problem is how the characters are arranged (format) or what kind of value it is at all (data type).

What you'll learn

Identify which data field validation technique stops a given bad entry before it reaches the database: a mandatory field, an input mask or format, a range or limit, a data type, or a check digit
Distinguish a data type check (whole number, decimal or text) from a format check (how the characters must be arranged), and recognize a check digit as a digit calculated from the others so that a typing mistake shows up

Aligned to

NIST 800-53

SI-10 Information Input Validation

CompTIA Tech+

5.3 Summarize methods used to interface with databases.

NIST NICE

S0565 Skill in implementing input validation.

K1147 Knowledge of data integrity principles and practices.

Key terms

Validation Rule: A condition applied to a data field that restricts input to acceptable values, formats, or ranges before data is accepted into a database.
Data Type: A classification that specifies what kind of value a database field can hold, such as integer, decimal, or string.
Check Digit: A calculated digit appended to a number, such as an ISBN, that allows a database to verify the accuracy of the entered data.
Input Validation: The process of enforcing rules on user-supplied data to ensure it conforms to expected type, length, format, and content before it is processed by an application.
Domain Integrity: A database integrity rule that enforces valid entries for a given column by restricting the format, type, and range of values allowed.

Topics

Database Integrity Input Validation Interactive Categorize

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