Consider a database with the following schema:

A black text on a white backgroundDescription automatically generated with low confidence

The Catalog relation lists the prices charged for parts by Suppliers.

Consider three transactions T$1,$ T$2,$ and T$3.$

T$1$ always has SQL isolation level SERIALIZABLE.

We first run T$1$ concurrently with T$2$ and then we run T$1$ concurrently with T$2$ but we change

the isolation level of T$2$ as specified below. Give a database instance and SQL statements for

T$1$ and T$2$ such that result of running T$2$ with the first SQL isolation level is different from

running T$2$ with the second SQL isolation level. Also specify the common schedule of T$1$ and T$2.$

Also explain why the results are different.

$1.$ SERIALIZABLE versus REPEATABLE READ. $(2\mathrm{.}5$ marks$)$

$2.$ REPEATABLE READ versus READ COMMITTED. $(2\mathrm{.}5$ marks$)$