Structured Query Language (SQL)

Introduction

Structured Query Language (SQL) is a standard programming language used to manage and manipulate Relational Database Management Systems (RDBMS). SQL allows users to perform various operations on databases, such as querying, inserting, updating, and deleting data.

SQL is widely used in web applications, enterprise systems, banking, and data analytics due to its efficiency in handling structured data.

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Key Features of SQL

✅ Declarative Language – Users specify what they want, not how to do it.
✅ Standardized – Used by all major RDBMS like MySQL, PostgreSQL, Oracle, SQL Server.
✅ Scalable – Efficiently handles large datasets.
✅ ACID Compliance – Ensures data integrity, security, and consistency.

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Types of SQL Commands

Category	Commands	Purpose

Data Query Language (DQL)

SELECT

Retrieve data from tables

Data Definition Language (DDL)

CREATE, ALTER, DROP, TRUNCATE

Define or modify database schema

Data Manipulation Language (DML)

INSERT, UPDATE, DELETE

Add, modify, or remove data

Data Control Language (DCL)

GRANT, REVOKE

Manage user permissions

Transaction Control Language (TCL)

COMMIT, ROLLBACK, SAVEPOINT

Manage transactions