top of page

Different Types of SQL Commands and Their Uses


SQL Command

SQL commands can be broadly categorised into several types based on their functionality and purpose in interacting with databases. Here are the main types of SQL commands:

1. Data Manipulation Language (DML) Commands:

DML commands are used to manipulate data stored in the database. They include:

EXPLAIN: Used to obtain information about how a SQL statement is executed. INSERT: Adds new rows of data into a table.

UPDATE: Modifies existing data in a table.

DELETE: Removes one or more rows from a table. LOCK: Used to lock database objects such as tables, rows.


2. Data Definition Language (DDL) Commands:

DDL commands are used to define, alter, and drop database objects such as tables and indexes. They include:

CREATE: Creates new database objects like tables, views, indexes, and sequences.

ALTER: Modifies the structure of existing database objects.

DROP: Deletes database objects from the database. TRUNCATE: Used to quickly delete all rows from a table by keeping table schema.

3. Data Control Language (DCL) Commands:

DCL commands are used to control access to the database and its objects. They include:

GRANT: Gives specific privileges to database users.

REVOKE: Removes previously granted privileges from database users.

4. Transaction Control Commands (TCL):

Transaction control commands manage the changes made to the database within a transaction. They include:


COMMIT: Saves the changes made in the current transaction.

ROLLBACK: Reverts the changes made in the current transaction.

SAVEPOINT: Creates a point in the transaction to which you can later roll back.

5. Data Query Language (DQL) Commands:

DQL commands are used to retrieve data from the database. The primary DQL command is:


SELECT: Retrieves data from one or more tables based on specified criteria.


Conclusion:

Understanding the different types of SQL commands and their functionalities is crucial for effectively interacting with databases. Whether you're retrieving data, modifying database structures, or managing user privileges, having a strong grasp of SQL commands empowers you to work efficiently and effectively with relational databases.

2 Comments

Rated 0 out of 5 stars.
No ratings yet

Add a rating
Guest
Apr 17
Rated 5 out of 5 stars.
Like

Guest
Apr 16
Rated 5 out of 5 stars.
Like
bottom of page