School Database Management System

A comprehensive Java-based database management system for educational institutions, demonstrating object-oriented programming principles through multi-level inheritance, file I/O operations, and a full-featured menu-driven interface.

📋 Table of Contents

• Overview
• Features
• Class Structure
• Getting Started
• Usage
• Technical Highlights
• What I Learned
• Future Enhancements
• Author

🎯 Overview

This project implements a school database management system that manages courses, faculty, students, and general staff through a hierarchical class structure. Built as part of CMP 158 at Lehman College, it demonstrates core computer science concepts including inheritance, polymorphism, file I/O, and exception handling.

Key Statistics

• 7 Classes with inheritance relationships
• 3-Level Inheritance Hierarchy
• 15 CRUD Operations via menu interface
• ~1,600 Lines of Code
• 100% Functional with comprehensive error handling

✨ Features

Core Functionality

• ✅ Create and manage courses, faculty, students, and general staff
• ✅ Add courses to faculty teaching schedules
• ✅ Enroll students in courses and track credits
• ✅ Query system for specific faculty, students, or courses
• ✅ Find min/max values (courses, credits, teaching loads)
• ✅ Persistent data storage via file I/O
• ✅ Menu-driven console interface with 15 operations

Advanced Features

• ✅ Custom sorting via Comparable interface implementation
• ✅ Object equality checking with overridden equals() methods
• ✅ Formatted output via toString() overrides
• ✅ Exception handling for file operations
• ✅ Defensive programming with boundary checks
• ✅ Static variable tracking for auto-generated IDs

🏗️ Class Structure

Inheritance Hierarchy

Person (Base Class)
├── Employee
│   ├── Faculty
│   └── GeneralStaff
└── Student

Course (Standalone - implements Comparable<Course>)

Class Responsibilities

Person (Base Class)

• Stores: name, birthYear
• Implements: Comparable<Person>
• Compares by: birthYear

Employee (extends Person)

• Stores: deptName, employeeID (auto-generated)
• Implements: inherited Comparable
• Compares by: employeeID
• Tracks: total number of employees (static)

Student (extends Person)

• Stores: major, isGraduate, studentID (auto-generated), coursesTaken (ArrayList)
• Implements: inherited Comparable
• Compares by: total credits earned
• Tracks: total number of students (static)

Faculty (extends Employee)

• Stores: isTenured, coursesTaught (ArrayList)
• Implements: inherited Comparable
• Compares by: number of courses taught
• Max capacity: 100 courses

GeneralStaff (extends Employee)

• Stores: duty (job responsibility)
• Implements: inherited Comparable
• Inherits comparison from Employee

Course (Standalone)

• Stores: isGraduateCourse, courseDept, courseNum, numCredits
• Implements: Comparable<Course>
• Compares by: courseNum

🚀 Getting Started

Prerequisites

• Java Development Kit (JDK) 8 or higher
• Any Java IDE (IntelliJ IDEA, Eclipse, VS Code) or command line

Installation

1. Clone the repository

git clone https://github.com/FidelAP-19/School-Database-System.git
cd School-Database-System

2. Compile the project

javac *.java

3. Run the application

java Main

Input File Format

Create a file named SchoolDB_Initial.txt with the following format:

Course: true,777,CMP,4
Faculty: John Smith,1980,Computer Science,true
Student: Jane Doe,2000,Computer Science,false
GeneralStaff: Bob Johnson,1975,Facilities,Maintenance

Format Rules:

• Each line starts with object type: Course:, Faculty:, Student:, or GeneralStaff:
• Fields are comma-separated
• Boolean values: true or false

💻 Usage

Menu Options

When you run the program, you'll see a menu with 15 operations:

=== MENU ===
1.  Create 3 New Courses
2.  Create 3 New Faculty
3.  Create 3 New General Staff
4.  Create 3 New Students
5.  Add 2 Courses to Faculty
6.  Add 2 Courses to Student
7.  Add Array of 2 Courses to Faculty
8.  Add Array of 2 Courses to Student
9.  Get Course from Faculty by Index
10. Get Course from Student by Index
11. Query Faculty for Course
12. Faculty with Most/Least Courses
13. Find Min/Max Course
14. Student with Most/Least Credits
15. Display All Data
0.  Exit and Save

Example Usage

Creating a New Course:

Enter choice: 1

--- Enter 3 New Courses ---
Course 1:
Are you a Graduate course? (true/false): false
Enter Course Number: 168
Enter Course Department: CMP
Enter Number of Credits: 4

Adding Courses to a Student:

Enter choice: 6

Which student? (Enter index): 0
Which course? (Enter index): 0
Course added successfully!

🔧 Technical Highlights

Object-Oriented Design

Inheritance Hierarchy

• 3-level deep inheritance demonstrating class relationships
• Proper use of super() for parent class initialization
• Method overriding for specialized behavior

Polymorphism

// Collections can hold parent type with child objects
ArrayList<Person> people = new ArrayList<>();
people.add(new Student("Alice", 2000, "CS", false));
people.add(new Employee("Bob", 1985, "IT"));

Encapsulation

• All fields are private
• Public getters/setters for controlled access
• Defensive copying where appropriate

Data Structures

ArrayList Usage

private ArrayList<Course> coursesTaught;  // Faculty's courses
private ArrayList<Course> coursesTaken;   // Student's courses

Benefits:

• Dynamic sizing (no fixed array limits)
• Built-in methods (add, get, size)
• Type safety with generics

File I/O & Exception Handling

try {
    FileInputStream fbs = new FileInputStream("SchoolDB_Initial.txt");
    Scanner inFS = new Scanner(fbs);
    // Process file...
    inFS.close();
} catch (FileNotFoundException e) {
    System.out.println("Cannot find file");
} catch (IOException e) {
    System.out.println("Error reading file");
}

Custom Sorting with Comparable

@Override
public int compareTo(Student other) {
    int thisCreditTotal = calculateTotalCredits();
    int otherCreditTotal = other.calculateTotalCredits();
    
    if (thisCreditTotal > otherCreditTotal) return 1;
    if (thisCreditTotal < otherCreditTotal) return -1;
    return 0;
}

Defensive Programming

Boundary Checking:

public Course getCourseTaken(int index) {
    if (index < 0 || index >= coursesTaken.size()) {
        return null;  // Safe return instead of crash
    }
    return coursesTaken.get(index);
}

Capacity Limits:

public void addCourseTaught(Course course) {
    if (coursesTaught.size() < 100) {  // Prevent overflow
        coursesTaught.add(course);
    }
}

Static Variables for ID Generation

public class Student extends Person {
    static private int numStudents = 0;  // Shared across all instances
    private int studentID;
    
    public Student() {
        numStudents++;                    // Increment counter
        studentID = numStudents;          // Auto-generate unique ID
    }
}

📚 What I Learned

Core Concepts

• ✅ Multi-level Inheritance - Building complex class hierarchies
• ✅ Polymorphism - Using parent types to reference child objects
• ✅ Encapsulation - Protecting data with private fields and public methods
• ✅ Abstraction - Separating interface from implementation

Java-Specific Skills

• ✅ Comparable Interface - Custom sorting logic
• ✅ Method Overriding - equals(), toString(), compareTo()
• ✅ ArrayList Collections - Dynamic data structures
• ✅ File I/O - Reading/writing persistent data
• ✅ Exception Handling - Graceful error recovery
• ✅ Static vs Instance - Understanding class-level vs object-level data

Software Engineering Practices

• ✅ Code Organization - Logical class structure
• ✅ Defensive Programming - Null checks, boundary validation
• ✅ User Input Validation - Preventing invalid data
• ✅ Documentation - Clear comments and method signatures

Problem-Solving

• ✅ String Parsing - Converting file data to objects
• ✅ Data Validation - Ensuring data integrity
• ✅ Menu-Driven Architecture - Building interactive applications
• ✅ Algorithm Design - Finding min/max, calculating totals

🎓 Academic Context

Course: CMP 158 - Programming Methods II
Institution: Lehman College, City University of New York (CUNY)
Semester: Fall 2024

This project served as the capstone assignment, demonstrating mastery of:

• Object-oriented programming principles
• Java collections framework
• File I/O and exception handling
• Software design and architecture

📁 Project Structure

School-Database-System/
├── Person.java              # Base class for all people
├── Employee.java            # Base class for employees
├── Student.java             # Student class with course tracking
├── Faculty.java             # Faculty with teaching assignments
├── GeneralStaff.java        # General staff with duties
├── Course.java              # Course information
├── Main.java                # Entry point (basic version)
├── Driver_SchoolDB.java     # Full menu-driven application
├── SchoolDB_Initial.txt     # Sample input data
└── README.md                # This file

🤝 Contributing

This is an educational project, but feedback and suggestions are welcome!

1. Fork the repository
2. Create a feature branch (git checkout -b feature/improvement)
3. Commit your changes (git commit -am 'Add new feature')
4. Push to the branch (git push origin feature/improvement)
5. Open a Pull Request

📄 License

This project is open source and available under the MIT License.

👤 Author

Fidel Perez

• GitHub: @FidelAP-19
• LinkedIn: Fidel Perez
• Portfolio: fidelperez.dev

🙏 Acknowledgments

• Institution: Lehman College, City University of New York (CUNY)
• Course: Programming Methods II

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