SQL Four languages: DDL,DML,DCL,TCL

1.DDL(data definition Language) database Definition Language statements is used to define the Database structure or schema.

DDL is SQL One of the four functions of the language.
DDL does not require a commit.
create
alter
drop
truncate
comment
rename

2. DML (data manipulation Language ) data manipulation language statements is used for managing data within schema objects.

Provided by the DBMS for use by a user or programmer to implement operations on data in a database.
DML is divided into two classes: interactive DML and embedded DML.
Depending on the level of the language, DML can be divided into procedural DML and non-procedural DML two species.
A commit is required.
SELECT
INSERT
UPDATE
DELETE
MERGE
Pager
EXPLAIN PLAN
LOCK TABLE

3.DCL（Data Control Language）Database Control LanguageAuthorization, role control, etc.
Grant Authorization
REVOKE Cancel Authorization

4.TCL（Transaction Control Language）Transaction Control Language
SavePoint to set the save point
ROLLBACK rollback
SET TRANSACTION

SQL is divided into four main parts :
(1) Data definition. (SQL DDL) to define the creation and undo operations of SQL schemas, basic tables, views, and indexes.
(2) Data manipulation. (SQL DML) data manipulation is divided into two categories: Data query and Data update. Data update is divided into three kinds of operations, inserting, deleting, and modifying.
(3) Data control. Includes authorization for basic tables and views, description of integrity rules, transaction control, and so on.
(4) The use of Embedded SQL rules. involves embedding rules that SQL statements use in the host language program.

SQL Four languages: DDL,DML,DCL,TCL