Question

A database has two tables Rand S with 100 tuples each. Exactly two transactions, 11 and T2, execute concurrently on the database. T1 inserts a tuple in R and after some time decides to abort. T2 computes the difference: SELECT count(*) from R - SELECT count(*) from s and inserts as many tuples in S. After the transactions complete, R has 100 tuples and S has 101 tuples. Which of the following is possible?
a. The transactions executed in the REPEATABLE READ isolation level.
b. The transactions executed in the READ UNCOMMITTED isolation level.
C. The transactions executed in the READ COMMITTED isolation level.
d. This outcome is not possible in any of these isolation levels.

Answer 1

Answer:

a. The transaction executed in the REPEATABLE READ isolation level.

Explanation:

Database management system are used by businesses to organize and handle large data. There are 3 types of DBMS :

1- Hierarchical Database management system

2- Network Database management system

3- Object oriented Database management system.