Q19

Consider the following tables $T1$ and $T2.$

$$\overset{T1}{\begin{array}{|c|c|c|} \hline \textbf {P} & \textbf {Q} \\\hline \text {2} & \text{2 }\\\hline \text{3} & \text{8} \\\hline \text{7} & \text{3} \\\hline \text{5} & \text{8} \\\hline \text{6 } &\text{9} \\\hline \text{8} & \text{5} \\\hline \text{9} & \text{8} \\\hline \end{array}} \qquad \overset{T2}{\begin{array}{|c|c|c|} \hline \textbf {R} & \textbf {S} \\\hline \text {2} & \text{2 }\\\hline \text{8} & \text{3} \\\hline \text{3} & \text{2} \\\hline \text{9} & \text{7} \\\hline \text{5 } &\text{7} \\\hline \text{7} & \text{2} \\\hline \end{array}}$$

In table $T1$ P is the primary key and Q is the foreign key referencing R in table $T2$ with on-delete cascade and on-update cascade. In table $T2,$ R is the primary key and S is the foreign key referencing P in table $T1$ with on-delete set NULL and on-update cascade. In order to delete record $\langle 3, 8 \rangle$ from the table $T1,$ the number of additional records that need to be deleted from table $T1$ is _______