Q: 41 Which two statements complete a transaction? (Choose two.)
A. DELETE employees;
B. DESCRIBE employees;
C. ROLLBACK TO SAVEPOINT C;
D. GRANT SELECT ON employees TO SCOTT;
E. ALTER TABLE employees
SET UNUSED COLUMN sal;
F. SELECT MAX(sal)
FROM employees
WHERE department_id = 20;
Answer: D, E
解：
When Does a Transaction Start and End?
A transaction begins when the first DML statement is encountered and ends when one of the
following occurs:
• A COMMIT or ROLLBACK statement is issued
• A DDL statement, such as CREATE, is issued
• A DCL statement is issued
• The user exits iSQL*Plus
• A machine fails or the system crashes
After one transaction ends, the next executable SQL statement automatically starts the next
transaction.
A DDL statement or a DCL statement is automatically committed and therefore implicitly ends a
transaction.
SELECT Data retrieval
INSERT
UPDATE
DELETE
MERGE Data manipulation language (DML)
CREATE
ALTER
DROP
RENAME
TRUNCAZTE Data definition language (DDL)
COMMIT
ROLLBACK
SAVEPOINT Transaction control
GRANT
REVOKE Data control language (DCL)
