SQL (Structured Query Language) is a database query language designed for storing, managing, querying, and manipulating relational databases.
Thank you for reading this post, don't forget to subscribe!- It allows users to perform tasks such as retrieving data, inserting records, updating data, and managing database structures.
Objectives of SQL:
- Data Retrieval (Querying):
- SQL provides commands like SELECT to retrieve specific data from one or more tables. It supports filtering, sorting, grouping, and aggregating data to meet specific requirements.
- Data Manipulation:
- SQL enables users to insert (INSERT), update (UPDATE), and delete (DELETE) records in a database.
- Database Structure Management:
- SQL includes commands to create, modify, and delete database structures like tables, indexes, and views using Data Definition Language (DDL) commands (CREATE, ALTER, DROP).
- Data Integrity and Security:
- SQL helps enforce data integrity through constraints (PRIMARY KEY, FOREIGN KEY, NOT NULL, etc.) and provides mechanisms for securing data, such as user authentication and authorization.
- Transaction Management:
- SQL allows control over database transactions to ensure data consistency and integrity using commands like BEGIN, COMMIT, and ROLLBACK.
- Portability and Standardization:
- SQL is a widely adopted standard across relational database systems (e.g., MySQL, PostgreSQL, Oracle, SQL Server), making it a portable and universally accepted language for interacting with databases.
Types of SQL Commands:
- Data Definition Language (DDL)
- Data Manipulation Language (DML)
- Data Control Language (DCL)
- Transaction Control Language (TCL)