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

INSTOCK

$\backslash$table$[[$Pid$,$Inventory location,productsinStock$],[1,$Jeddah,$5000],[2,$Jeddah,$3500],[2,$Riyadh,$2500],[3,$Riyadh,$3000],[1,$Dammam,$1500],[3,$Dammam,$3000]]$

PRODUCT

$\backslash$table$[[$Pid$,$name,price$],[1,\backslash$table$[[$Color$],[$Pencil$]],10],[2,$Eraser,$5],[3,$Ink,$10]]$

$\backslash$table$[[$T$1,$T$2,$T$3],[$SELECT productInStock,INSERT INTO INSTOCK,SELECT sum$($productinStock$)],[$FROM INSTOCK,VALUES $(1,$ "Taif", $4000),$FROM INSTOCK$],[$WHERE pid$=1,,],[$INSERT INTO PRODUCT,,$],[$VALUES $(4,$ "note book", $3),,],[$SELECT productInStock,,$],[$FROM INSTOCK,,$],[$WHERE pid$=1,,]]$

Assumptions:

$1-$ Transaction isolation levels are READ COMMITTED.

$2-$ Individual statements are executed atomically.

Show how non$-$serializable behavior is exhibited when transactions are executed concurrently.

Decide the minimum isolation levels needed for the transactions to ensure serializable behavior. Justify.

Notes on grading: This question will be graded based on the correct results $[5\%],$ correct isolation levels $[5\%],$ correct justification$(5\%,$ and the quality of the answer $[5\%].$