Employee Management System — SQL

A relational database project built using Oracle SQL to manage employees, departments, projects, salaries, and employee-project assignments.

📌 Project Overview

The Employee Management System demonstrates practical SQL concepts through a realistic employee database.

The project focuses on database design, relationships between tables, data retrieval, aggregation, joins, subqueries, window functions, and views.

🛠️ Technology

• Oracle SQL
• Oracle Live SQL

🗂️ Database Structure

The project contains four main tables:

• DEPARTMENT — Stores department information.
• EMPLOYEE — Stores employee details, salary, job title, hiring date, department and manager relationships.
• PROJECT — Stores project information, budgets and project dates.
• EMPLOYEE_PROJECT — Junction table representing the many-to-many relationship between employees and projects.

📚 SQL Concepts Demonstrated

• DDL — CREATE TABLE, ALTER TABLE
• Constraints
• Primary Keys
• Foreign Keys
• Unique Constraints
• Check Constraints
• DML — INSERT
• SELECT
• WHERE
• ORDER BY
• Table Aliases
• INNER JOIN
• Multiple Table JOINs
• Aggregate Functions
• GROUP BY
• HAVING
• Subqueries
• Window Functions
• RANK()
• Views

📁 Project Structure

SQL-Employee-Management-System/
│
├── 01_tables.sql
├── 02_data.sql
├── 03_basic_queries.sql
├── 04_joins.sql
├── 05_aggregate_queries.sql
├── 06_subqueries.sql
├── 07_window_functions.sql
├── 08_views.sql
└── README.md

🎯 Key Learning Outcomes

This project helped demonstrate how SQL can be used to:

• Design relational database structures
• Establish relationships between tables
• Retrieve related data using JOINs
• Analyze employee salaries using aggregate functions
• Filter grouped data using HAVING
• Use subqueries for comparative analysis
• Rank employees using window functions
• Create reusable database views

👨‍💻 Author

Mohammed Shoaib P A

Java Full Stack Developer | Java | SQL | JDBC | Spring Boot