Data Type - Null Value

Data System Architecture


Every data type includes a special value, called the null value, sometimes denoted by the keyword NULL that reflects the optionality character of the value.

The data type of the null value implied by the keyword NULL cannot be inferred since the null value is in every data type

Although the null value is neither equal to any other value nor not equal to any other value — it is unknown whether or not it is equal to any given value.

A null is the absence of a value in a column of a row. Nulls indicate missing, unknown, or inapplicable data. A null should not be used to imply any other value, such as zero.

Null is the representation of “missing information and inapplicable information”.


Most programming languages use null as an absence of value. Ie the variable is not pointing to any value or object.

The meaning is implementation dependent and can represent the fact that:

  • the data was not processed
  • or the data is unknown


There is even a null character.

Discover More
Card Puncher Data Processing
(Data) Type - (Datatype|Type of data)

Variables, parameters, and function may be typed (static typing) and return values that are typed (as do a database column). The type of a variable or expression defines the characteristics of the values...
Java Conceptuel Diagram
Java - Null

in Java From java/util/objects java/util/objectsrequireNonNull java/util/objectsisNull nonNull See also: java/util/Optional. A container object which may or may not contain a non-null value....
Data System Architecture
SQL - Null

NULL value in SQL represents missing data in SQL. NULL has its own data domain and implements therefore its own behavior. The most important one being that: An equality comparison of two NULL values...
Data System Architecture
SQL - Sqllogictest

Sqllogictest is a program designed to verify that an SQL database engine computes correct results by comparing the results to identical queries from...
Data System Architecture
Three-valued logic (3VL)

A three-valued logic implements a boolean as having three possible values: true, false and some indeterminate third value. This third value comes in play when you want to retrieve a Boolean...
What is JSON (JavaScript Object Notation)?

JSON 99)) is a structured text format that stands for JavaScript Object Notation. It is a simple text format that can be used for representing nested structures of data (lists of...

Share this page:
Follow us:
Task Runner