Q2-iv

Match the pairs in the following questions:

$$\begin{array}{|ll|ll|}\hline (a) & \text{Secondary index} & (p) & \text{Function dependency} \\\hline (b) & \text{Non-procedural query language} & (q) & \text{B-tree} \\\hline (c) & \text{Closure of a set of attributes} & (r) & \text{Domain calculus} \\\hline (d) & \text{Natural join} & (s) & \text{Relational algebraic operations} \\\hline \end{array}$$