Everyone Should Know These SQL Commands List in DBMS

Summary: SQL commands list in DBMS help manage databases efficiently. This guide uses examples to explain DDL, DML, DQL, DCL, and TCL commands. Learn how to create, modify, retrieve, and secure data using SQL. Take your SQL skills to the next level with Pickl.AI’s Data Science courses.

Introduction

Imagine you have a giant digital notebook where all your important data is stored—SQL is the magic pen that helps you write, erase, and find information quickly. In simple words, SQL (Structured Query Language) is used to manage and organise data in databases. Without it, handling data would be a messy job!

In this blog, we’ll break down the SQL commands list in DBMS so you can understand how databases work effortlessly. Whether you’re a beginner or just curious, by the end, you’ll know how SQL commands list help store, retrieve, and manage data like a pro! 

Key Takeaways

• SQL commands help manage and organise database data efficiently.
• DDL, DML, DQL, DCL, and TCL serve different functions in SQL.
• SQL is essential for creating, modifying, retrieving, and securing databases.
• Mastering SQL enhances data handling skills and career opportunities.
• Enroll in Pickl.AI’s Data Science courses to learn SQL from basic to advanced levels.

Understanding SQL Commands

SQL commands are instructions used to interact with databases. They help users store, retrieve, update, and manage data efficiently. Just like giving commands to a computer, SQL commands tell the database what actions to perform. These commands are essential for organising and handling large amounts of information in a structured way.

How Are SQL Commands Categorised?

SQL commands are grouped based on their purpose. Each category serves a specific function:

• Data Definition Language (DDL): These commands help create and modify database structures, like tables.
• Data Query Language (DQL): It fetches data from the database.
• Data Manipulation Language (DML): These commands add, update, or delete data within a table.
• Data Control Language (DCL): It manages access permissions and security.
• Transaction Control Language (TCL): These commands help control and manage database transactions to maintain accuracy.

Data Definition Language (DDL)

Data Definition Language (DDL) is a set of SQL commands used to define and modify the structure of a database. It helps create, change, and remove database objects such as tables, indexes, and schemas. 

Simply put, DDL shapes the framework of a database, determining how data is organised and stored. Unlike other SQL commands, DDL does not manipulate actual data but focuses on defining the database’s blueprint.

Common DDL commands are: 

CREATE 

The CREATE command helps create new database objects such as tables, indexes, views, or stored procedures. It defines the structure by specifying column names, data types, and constraints.
Example:

ALTER 

The ALTER command updates the structure of a table without deleting existing data. You can add, modify, or delete columns.
Example:

DROP 

The DROP command permanently removes an entire database object, such as a table. Once dropped, data and structure cannot be recovered.
Example:

TRUNCATE

The TRUNCATE command deletes all rows from a table but keeps its structure intact. It is faster than DELETE because it does not log individual row deletions.
Example:

RENAME 

The RENAME command allows you to change the name of an existing table.

Example:

COMMENT 

The COMMENT command lets you add descriptions to database objects to improve documentation.
Example:

Data Query Language (DQL)

Data Query Language (DQL) retrieves information from a database. It helps users fetch specific data based on conditions or requirements. DQL does not modify or delete data; it simply extracts the needed information for display or further processing.

SELECT

The SELECT command is the most commonly used DQL statement. It allows users to fetch data from one or more tables in a structured manner. The result appears as a temporary table that stores the requested data.

Example:

Data Manipulation Language (DML)

Data Manipulation Language (DML) is a set of SQL commands that help modify and manage data within database tables. While Data Definition Language (DDL) defines the structure of a database, DML focuses on handling the actual data stored in it. 

With DML, you can insert new records, update existing ones, or remove unnecessary data from tables. These commands make it easy to manage and organise information dynamically.

Common DML commands are: 

INSERT 

The INSERT command allows you to add new records to a table. It defines the table name, column names, and values inserted.

Example:

UPDATE 

The UPDATE command helps change values in an existing table. It updates specific records based on a condition.

Example:

DELETE

The DELETE command removes records from a table. You can delete specific records using a condition.
Example:

LOCK 

The LOCK command locks a table to prevent other users from modifying it while a transaction is being executed.
Example:

CALL 

The CALL command runs a stored procedure, a pre-defined SQL program stored in the database.
Example:

EXPLAIN PLAN 

The EXPLAIN PLAN command details how an SQL query will be executed, helping users optimise performance.
Example:

Data Control Language (DCL)

Data Control Language (DCL) helps manage access to a database. It allows database administrators to grant or revoke permissions, ensuring that only authorised users can view or modify data. DCL enhances security by preventing unauthorised access and protecting sensitive information.

Common DCL commands are: 

GRANT 

The GRANT command allows administrators to permit users to perform specific actions on database objects like tables and views.
Example:

REVOKE

The REVOKE command removes previously granted permissions, restricting user access to database objects.
Example:

Transaction Control Language (TCL)

Transaction Control Language (TCL) ensures database integrity by completing a transaction fully or undoing it entirely if any operation fails. If any task within the transaction fails, TCL reverses the entire process to prevent inconsistent data. TCL ensures databases remain reliable and error-free.

Common TCL commands are: 

BEGIN TRANSACTION 

The BEGIN TRANSACTION command marks the beginning of a new transaction. It treats all the following operations as a single unit.
Example:

COMMIT

The COMMIT command saves all changes made during the transaction. Once committed, the changes become permanent and cannot be undone.
Example:

ROLLBACK

The ROLLBACK command undoes all changes made during the transaction. This command helps revert the database to its previous state if an error occurs.
Example:

SAVEPOINT

The SAVEPOINT command allows users to set a checkpoint within a transaction. If needed, they can roll back only to that specific point instead of undoing the entire transaction.
Example:

Other Essential SQL Commands

Below are some other necessary SQL commands that you should know:

• WHERE: Filters records based on specific conditions, making queries more precise.
• ORDER BY: Sorts query results in either ascending or descending order.
• JOIN: Combines data from multiple tables based on a common column, helping retrieve relational data.

In Closing

Mastering SQL commands list is essential for efficiently managing and organising databases. Whether you are retrieving, modifying, or securing data, understanding SQL commands simplifies database interactions. From beginners to advanced users, SQL is a valuable skill for anyone working with data.

If you want to deepen and apply your SQL knowledge to real-world projects, consider enrolling in Pickl.AI’s Data Science courses. These courses cover basic and advanced SQL, helping you build strong database management skills. Start your SQL learning journey today and unlock exciting data analytics and data science career opportunities!

Frequently Asked Questions

What are SQL commands in DBMS?

DBMS’s SQL commands are instructions to manage, retrieve, and modify database data. They include DDL, DML, DCL, DQL, and TCL categories.

Why is SQL important in database management?

SQL allows users to create, manipulate, and secure databases efficiently. It helps store, retrieve, and modify data, making it essential for managing structured data.

How can I learn SQL from beginner to advanced level?

You can learn SQL by taking online courses like Pickl.AI’s Data Science Program, which covers SQL basics and advanced techniques.