Q$4$: $[20\%]$ The following tables and transactions are given.

INSTOCK

PRODUCT

Assume that there are only three transactions in the system and that their isolation levels

are set to READ UNCOMMITTED. Considering the different possible schedules of the

transactions:

$($i$)$ What results will be returned by the select operations in T$1?$

$($ii$)$ What results will be returned by $T3?$

$($iii$)$ What are the recommended isolation levels for the transactions? Discuss.

Notes on grading: This question will be graded based on the correct results $[10\%],$ correct

isolation levels $[5\%],$ and the quality of the answer $[5\%].$