Database of four languages (DDL, DML, DCL, TCL)

1.DDL (data definition Language ) DB Definition Language statements is used to define the database structure O R schema.

DDL is one of the four functions of SQL language.
A three-level structure for defining a database, including external, conceptual, internal, and inter-image, defining constraints such as data integrity, security controls, and more
DDL does not require a commit.
CREATE
Alter
DROP
TRUNCATE
COMMENT
RENAME

2.DML (datamanipulation Language) Manipulation Language statements is used for managing data within schema OB Jects.

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 Language authorization, 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 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.

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What is DDL?
The DDL is the abbreviation of data definition Language, which means it is one of the four functions of SQL language.
A three-level structure for defining a database, including external, conceptual, internal, and inter-image, defining constraints such as data integrity, security controls, and so on.

What is DML?
DML is the abbreviation of data manipulation language, which is one of the four functions of SQL language, which means manipulation language.
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.

What is a DCL?
The DCL is the abbreviation of Data Control language, which means that it is one of the four functions of SQL language.

How is the composition of SQL divided into several parts?
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.

What's the difference between DDL, DML and DCL commands? 
DDL is Data Definition Language statements. Some examples: 
create-to CREATE objects in the database 
Alter-alters The structure of the DATABASE&N Bsp
Drop-delete objects from the database 
Truncate-remove all records from a table, including all spaces Allo cated for the records is removed 
Comment-add comments to the data dictionary 
grant-gives user ' s ACC ESS privileges to database 
Revoke-withdraw access privileges given with the GRANT command 
DML is Data Manipulation Language statements. Some Examples:

Select-retrieve data from the A database
Insert-insert data into a table
Update-updates existing data within a table
Delete-deletes all records from a table, the space for the records remain
Call-call a PL/SQL or Java Subprogram
EXPLAIN plan-explain access Path to data
LOCK Table-control concurrency
DCL is Data Control Language statements. Some Examples:

Commit-save work done
Savepoint-identify a point in a transaction to which can later roll back
Rollback-restore database to original since the last COMMIT
SET transaction-change TRANSACTION options like what rollback segment to use.

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Database of four languages (DDL, DML, DCL, TCL)