Now, let’s move to the next topic:

Indexes 🚀

🧠 1. What is an INDEX?

An INDEX is used to make data retrieval faster

👉 Think like a book 📚
- Without index → scan every page
- With index → jump directly to topic

Same happens in databases 💯

⚡ 2. Why Use Indexes?

✔ Faster SELECT queries
✔ Faster searching
✔ Better performance on large tables

❌ But:
- Uses extra storage
- INSERT/UPDATE become slightly slower

📊 Visual Understanding

⚡ 3. Create an INDEX
CREATE INDEX idx_salary
ON employees(salary);
👉 Creates index on salary column

🔍 4. Query Using Indexed Column
SELECT FROM employees
WHERE salary > 50000;
✔ Faster because of index

❌ 5. Drop an INDEX
DROP INDEX idx_salary ON employees;

🔥 6. Primary Key Automatically Creates Index
CREATE TABLE employees (
emp_id INT PRIMARY KEY,
name VARCHAR(50)
);

✔ PRIMARY KEY → automatically indexed

⚡ 7. Types of Indexes

- Primary Index: Created on primary key
- Unique Index: Prevent duplicate values
- Composite Index: Index on multiple columns

🎯 8. Composite Index Example
CREATE INDEX idx_dept_salary
ON employees(department, salary);

✔ Useful when filtering both columns together

🎯 9. Practice Tasks
1. Create index on employee name
2. Create index on department column
3. Create composite index on department + salary
4. Query employees using indexed column
5. Drop created index

⚡ Mini Challenge 🔥

👉 Create a unique index on email column

🔥 Indexes improve READ speed but may slow down INSERT / UPDATE

Double Tap ❤️ For More