Which of the following statement is true?
A. A Primary key is also a candidate key
B. Each relation has at least one foreign key
C. Foreign keys can't have null values
D. A Primary key is also an alternate key
Answer:A
Which of the following statement is true?
A. A Primary key is also a candidate key B. Each relation has at least one foreign key C. Foreign keys can't have null values D. A Primary key is also an alternate key