The transaction isolation levels define the type of locks acquired on the database objects, such as tables. Also, it defines the degree to which a transaction should be isolated from the data modifications made by any other transaction. A transaction isolation level can be set by the developer by invoking the following SQL statement:
SET TRANSACTION ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED}
The SET TRANSACTION ISOLATION LEVEL statement should be called inside a transaction block before any query, otherwise, it will have no effect. An alternative is to use the following syntax:
BEGIN TRANSACTION ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ ...
