What is meant by NULL value What are the reasons that lead to their occurrence in database relations - Accountancy - Structuring Database for Accounting

Question

What is meant by NULL value? What are the reasons that lead to
their occurrence in database relations?

Saurabh Mehta · Accepted Answer

The absence of a data
item which is represented by a special value is known as NULL
value
The following are
the reasons that lead to its occurrence in the database
relations
(i) When a
particular attribute does not apply to an entity
(ii) When the
existing value of an attribute is unknown
(iii) When the value is unknown because it does not exist

What is meant by NULL value? What are the reasons that lead to their occurrence in database relations?