Syntax database management berbasis SQL terbagi menjadi beberapa definisi yaitu: DDL, DML, DCL, TCL.
Berikut ini fungsi keempat definisi tersebut
1. DDL (Data Definition Language) :
Data Definition Language digunakan untuk membuat struktur database.
Contoh syntax dari DDL:
CREATE : to create objects in database
ALTER : alters the structure of database
DROP : delete objects from database
RENAME : rename an objects
Berikut ini adalah DDL yang membuat table bernama department:
create table department
(dept_name char(20),
building char(15),
budget numeric(12,2));
2. DML (Data Manipulation Language) :
Data Manipulation Language digunakan untuk memanipulasi data yang ada pada database
Contoh perintah DML:
SELECT: retrieve data from the database
INSERT: insert data into a table
UPDATE: update existing data within a table
DELETE: deletes all records from a table, space for the records remain
Contoh SQL query untuk menemukan nama semua instructors di dalam history department:
select instructor.name
from instructor
where instructor.dept_name = 'History';
3. TCL (Transaction Control Language) :'
Transaction Control Language digunakan untuk mengatur transaksi pada database. TCL nantinya digunakan untuk memanage perubahan pada DML. Dengan kata lain, TCL digunakan bersamaan dengan DML.
Contoh perintah TCL:
COMMIT: Commit command is used to permanently save any transaction
into the database.
ROLLBACK: This command restores the database to last committed state.
It is also used with savepoint command to jump to a savepoint
in a transaction.
SAVEPOINT: Savepoint command is used to temporarily save a transaction so
that you can rollback to that point whenever necessary.
DCL (Data Control Language) :
Data Control Language adalah syntax yang digunakan untuk memanajemen akses pada database.
Contoh perintah DCL :
GRANT: allow specified users to perform specified tasks.
REVOKE: cancel previously granted or denied permissions.
The operations for which privileges may be granted to or revoked from a user or role apply to both the Data definition language (DDL) and the Data manipulation language (DML), and may include CONNECT, SELECT, INSERT, UPDATE, DELETE, EXECUTE and USAGE.
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