Example 1: Starting a Default Transaction in a Multistatement
    Procedure or as a Single Statement

    SQL> START DEFAULT TRANSACTION;
    SQL>
    SQL> BEGIN
    cont> COMMIT;
    cont> START DEFAULT TRANSACTION;
    cont> END;
    SQL>
    SQL> ROLLBACK;

    Example 2: Starting Several Variations of the START TRANSACTION
    Statement

    SQL> START TRANSACTION READ WRITE,
    cont>   ISOLATION LEVEL READ COMMITTED;
    SQL> COMMIT;
    SQL>
    SQL> -- Defaults to serializable
    SQL> START TRANSACTION READ WRITE;
    SQL> COMMIT;
    SQL>
    SQL> -- Defaults to read write
    SQL> START TRANSACTION ISOLATION LEVEL READ COMMITTED;
    SQL> ROLLBACK;
    SQL>
    SQL> -- Defaults to read write serializable
    SQL> START TRANSACTION;
    SQL>
    SQL> BEGIN
    cont> COMMIT;
    cont> START TRANSACTION
    cont>     ISOLATION LEVEL READ COMMITTED,
    cont>     READ WRITE;
    cont> END;
    SQL> COMMIT;