DBI202Xuất hiện trong 1 đề thi
Which of the following is not one of Armstrong's axioms for inference of functional dependencies?
Các lựa chọn
AIf $Y \subseteq X$ then $X \to Y$
BIf $X \to Y$ then $XZ \to YZ$
CIf $X \to Y$ and $Y \to Z$ then $X \to Z$
DIf $X \to YZ$ then $X \to Y$ and $Y \to Z$