Explanation:None. 2. If the attribute phone number is included in the relation all the values need not be entered into the phone number column . This type of entry is given as
A. 0
B. –
C. Null
D. Empty space
Answer:A
Explanation:None. 2. If the attribute phone number is included in the relation all the values need not be entered into the phone number column . This type of entry is given as
A. 0 B. – C. Null D. Empty space
Explanation:Null is used to represent absence of a value. 3. The predicate in a where clause can involve Boolean operations such as and.The result of true and unknown is_______, false and unknown is _____, while unknown and unknown is _____.