DBI202Xuất hiện trong 1 đề thi
Suppose that we have a relation $R(B,C,D)$ that satisfies FD's: $D\to B$ and $D\to C$. Which of the following FD is equivalent to the given dependency functions?
Các lựa chọn
A$D\to BC$
B$D\to DB$
C$DB\to B$
D$DC\to DB$