🚀 Using Indexes in Oracle SQL to Improve Query Performance

As part of my continued learning with Oracle Autonomous Database, I explored how indexes can improve query performance in SQL. Indexes help databases retrieve data faster, especially when working with large datasets.

🎯 Objective

The goal of this activity was to:

• Understand what indexes are

• Learn how to create an index

• Improve query performance

💻 Step 1: Creating the Table

CREATE TABLE employees (
  emp_id NUMBER,
  emp_name VARCHAR2(50),
  department VARCHAR2(50),
  salary NUMBER
);

🧪 Step 2: Inserting Data

INSERT INTO employees VALUES (1, 'Ali', 'IT', 50000);
INSERT INTO employees VALUES (2, 'Ahmed', 'HR', 70000);
INSERT INTO employees VALUES (3, 'Sara', 'IT', 60000);
INSERT INTO employees VALUES (4, 'Zara', 'HR', 65000);

⚡ Step 3: Creating an Index

CREATE INDEX idx_salary ON employees(salary);

This index helps speed up queries that filter by salary.

🔍 Step 4: Querying Data

SELECT * FROM employees WHERE salary > 60000;💡 What I Learned

• What indexes are and why they are useful

• How to create an index in Oracle SQL

• Improving query performance

🚀 Conclusion

This activity helped me understand how indexes optimize database queries. Indexes are an essential concept in database performance tuning and are widely used in real-world applications.