ISRO2015-20

Question

Let $\text{R = (A, B, C, D, E, F)}$ be a relation scheme with the following dependencies $\text{C} \rightarrow \text{F, E} \rightarrow \text{A}, \text{EC} \rightarrow \text{D, A} \rightarrow \text{B}$. Which of the following is a key of $\text{R}?$

• A. $\text{CD}$
• B. $\text{EC}$
• C. $\text{AE}$
• D. $\text{AC}$

Answer 1

EC-->D    {CDE}

C-->F      {CDEF}

E-->A       {ACDEF}

A-->B       {ABCDEF}

EC IS KEY

Answer 2

EC is minimal Super key which can derive all the attributes of relation...