Pregunta

Given the following functional dependencies: ABD -> C and C -> B

is that then enough to say that AD -> C?

The rationale being that you would get ABD -> CB, and then B can be removed from both sides.

¿Fue útil?

Solución

A+ = {A}
B+ = {B}
C+ = {B,C}   
D+ = {D}
AD+ = {A,D} 

You cannot remove them from both sides,just like you cannot remove C from both sides in C+ shown above. So the answer is that those two FDs are not sufficient to say that AD->C

Licenciado bajo: CC-BY-SA con atribución
No afiliado a StackOverflow
scroll top