🔐 DCL (Data Control Language) in SQL

Last Updated: January 2026

DCL (Data Control Language) is a category of SQL commands used to control access and permissions in a database.

👉 DCL decides who can do what in the database.

In real-world databases:

  • Multiple users exist
  • Not everyone should access all data
  • Permissions must be controlled

DCL helps to:

  • Grant permissions
  • Remove permissions
  • Protect sensitive data

Hinglish Tip 🗣: Database me rights aur permissions control karna ho — kaun read kare, kaun write kare — tab DCL use hota hai.

CREATE USER

The CREATE USER command is used to create a new user in a database.

CREATE USER user_name@host_name IDENTIFIED BY 'password';
  • host_name: The name of the host that the user is allowed to connect from,it can be:
    • localhost (127.0.0.1)
    • IP address (244.178.44.111)
    • Subdomain (%.example.com )
    • domain name (example.com)
    • % (all hosts)
  • user_name: The name of the user to be created
  • password: The password for the user

Hinglish Tip 🗣: Jab database me new user banane ho, tab CREATE USER command use hota hai.

Example:

CREATE USER 'admin'@'%' IDENTIFIED BY 'password';

VIEW USERS

The VIEW USERS command is used to view all users in a database.

SELECT * FROM mysql.user;

DROP USER

The DROP USER command is used to remove a user from a database.

DROP USER user_name@host_name;

Change User Password

The SET PASSWORD command is used to change the password of a user in a database.

-- Only Work if user is already login
SET PASSWORD = "new_password";

-- OR
SET PASSWORD FOR user_name@host_name = PASSWORD('new_password');

-- OR
ALTER USER user_name@host_name IDENTIFIED BY 'new_password';

🧩 DCL Commands

We will cover each command separately in upcoming tutorials.

GRANT

  • Gives permissions to users
  • Controls what operations are allowed
GRANT SELECT ON table_name TO user;

REVOKE

  • Removes previously granted permissions
  • Restricts access
REVOKE SELECT ON table_name FROM user;

🔑 Common Permissions in DCL

  • SELECT
  • INSERT
  • UPDATE
  • DELETE
  • ALL

⚠️ Important Characteristics of DCL

  • Affects database security
  • Used mostly by DB admins
  • Permissions apply at database or table level
  • Changes are usually auto-committed
← PreviousNext →