Chapter 2, Problem 16E

Explanation of Solution

Null values:

• The null values are used to indicate that the value is not present in the current location.
• The null values can be indicated by a space or zero or any other default value.
• If a field contains null value means that content of the cell is unknown at the time of looking at it.
• For example, an employee whose address has changed and the new address is not yet known. So this address should be indicated using a null value...