> For the complete documentation index, see [llms.txt](https://nightly.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nightly.gitbook.io/docs/database/home.md).

# Home

## 🧠 SQL Introduction

SQL means Structured Query Language. It is a standardized language used to interact with relational databases.

## 🎯 What is SQL used for?

SQL allows:

* Create and organize databases (tables, relationships, etc.)
* Read data (with queries like SELECT)
* Add (INSERT), modify (UPDATE) or delete (DELETE) data
* Manage security, access rights and performance

### 🔧 How does SQL work?

Data is stored in tables, much like a spreadsheet:

* Each line = one record (ex: one user)
* Each column = one field (ex: name, email, age)

Example of user table:

| id | name  | email               |
| -- | ----- | ------------------- |
| 1  | Alice | <alice@exemple.com> |
| 2  | Bob   | <bob@exemple.com>   |

### 📌 Some basic commands:

* SELECT \* FROM users; read all data
* INSERT INTO users (name, email) VALUES ('Charlie', '<charlie@exemple.com>');
* UPDATE users SET email = '<bob@newmail.com>' WHERE id = 2;
* DELETE FROM users WHERE id = 1;

### 🛠️ Where is SQL used?

SQL is used in most modern applications: websites, enterprise software, cloud services, etc. Systems like MySQL, PostgreSQL, SQLite, SQL Server use SQL.