Question

List two reasons why null values might be introduced into the database.

Answer 1

Nulls may be introduced into the database because the actual value is either unknown or does not exist.


For example, an employee whose address has changed and whose new address is not yet known should be retained with a null address.

Answer 2

Null values are in databases

There are many reasons for this.

• One of the reasons of introducing null values in databases are that may be the actual value doesn’t exist or may be unknown.

• Null value is used to indicate missing or unknown values.  

• The word NULL is used to specify these values. NULL really isn't a specific value as much as it is a pointer.

Hope it helped......