What is true about Unique and primary key?
A. Unique can have multiple NULL values but Primary can’t have.
B. Unique can have single NULL value but Primary can’t have even single.
C. Both can have duplicate values
D. None of the Mentioned
Answer:A
What is true about Unique and primary key?
A. Unique can have multiple NULL values but Primary can’t have. B. Unique can have single NULL value but Primary can’t have even single. C. Both can have duplicate values D. None of the Mentioned
Explanation: primary key doesn’t allow Null values and Unique key allows Null value, but only one Null value.