特此一記，省得忘。
1.DDL （Data Definition Language ）數(shù)據(jù)庫(kù)定義語(yǔ)言 statements are used to define the database structure or schema.
DDL不需要commit.
CREATE
ALTER
DROP
TRUNCATE
COMMENT
RENAME
2.DML （Data Manipulation Language）數(shù)據(jù)操縱語(yǔ)言 statements are used for managing data within schema objects.
需要commit.
SELECT
INSERT
UPDATE
DELETE
MERGE
CALL
EXPLAIN PLAN
LOCK TABLE
3.DCL（Data Control Language）數(shù)據(jù)庫(kù)控制語(yǔ)言 授權(quán)，角色控制等
GRANT 授權(quán)
REVOKE 取消授權(quán)
4.TCL（Transaction Control Language）事務(wù)控制語(yǔ)言
SAVEPOINT 設(shè)置保存點(diǎn)
ROLLBACK 回滾
SET TRANSACTION