Library Management System

Object-Oriented Programming Assessment

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Overview

In this project you will finish building a Library Lending Manager — a small Python application that manages a collection of books, DVDs, and magazines. The starter code gives you a working foundation. Your job is to complete the missing pieces, connect them together, and make the system functional.

By the end of this project your application should allow a user to:

• Add new items to the library
• Search for items by title or author
• Check out and return items
• View overdue items and active customer loans

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Project Structure

OOP/
├── main.py                  # Entry point — contains the menu and user interface
├── setup_database.py        # Run this once to create your database
│
├── src/
│   ├── library_item.py      # PROVIDED — abstract base class for all items
│   ├── book.py              # COMPLETE ME — Book class
│   ├── dvd.py               # COMPLETE ME — DVD class
│   ├── magazine.py          # COMPLETE ME — Magazine class
│   └── database_manager.py  # PROVIDED — handles all database operations
│
├── database/
│   ├── schema.sql           # PROVIDED — database table definitions
│   └── seed_data.sql        # PROVIDED — sample data loaded on setup
│
└── tests/
    └── test_library.py      # COMPLETE ME — write your tests here

PROVIDED files are fully implemented. Read them to understand how they work, but you should not need to modify them.

COMPLETE ME files have TODO comments marking the code you need to write.

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Getting Started

1. Set up your database (run this once):

python setup_database.py

2. Run the application:

python main.py

3. Run your tests:

python tests/test_library.py

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What You Need to Implement

1. Complete the child classes (src/book.py, src/dvd.py, src/magazine.py)

Each class already has its constructor and properties written for you. Your task is to implement the three abstract methods that every item type must have:

Method	What it should do
loan_duration_days()	Return the number of days this item type can be borrowed
calculate_late_fee(days_overdue)	Return the total late fee as a float
details()	Return a dictionary of all item attributes

Refer to the class attributes (late_rate, loan_period_days) already defined at the top of each class.

Loan periods and late rates:

Type	Loan Period	Late Fee
Book	14 days	$0.25 / day
DVD	3 days	$0.50 / day
Magazine	7 days	$0.10 / day

2. Complete the menu methods in main.py

The view_all_items() method is fully implemented as a working example — read it carefully to understand the pattern. Then implement the remaining methods, each marked with a TODO comment:

• add_item_menu() — collect input and add a new item
• search_items() — search and display results
• checkout_item_menu() — process a checkout
• return_item_menu() — process a return
• view_overdue_items() — display overdue items
• view_customer_checkouts() — display a customer's active loans

Each TODO includes hints about which DatabaseManager method to call.

3. Write tests in tests/test_library.py

Several example tests are already written. Add your own to verify your implementations work correctly, including edge cases and invalid input.

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OOP Concepts to Demonstrate

Your completed project should clearly show all four pillars of OOP:

Concept	Where it appears
Abstraction	LibraryItem defines abstract methods that child classes must implement
Inheritance	Book, DVD, and Magazine all inherit shared fields and behavior from LibraryItem
Encapsulation	Attributes are protected (_name) and accessed through properties with validation
Polymorphism	Calling calculate_late_fee() on a Book, DVD, or Magazine produces different results

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Deliverables

Project Organization

Deliverable	Description
Repo Directory	Project uses the provided directory structure appropriately
README.md	Your README explains the project and how to run it
GitHub Repo	Project is pushed to your assigned GitHub repo — failure to push means the project will not be graded

Class Structures

Deliverable	Description
Abstract Base Class	LibraryItem serves as the abstract parent with abstract methods
Derived Classes	Book, DVD, and Magazine provide complete implementations of all abstract methods
Encapsulation	Protected attributes accessed and validated through property getters and setters
Abstraction	Menu code in main.py works with item objects without knowing their internal details
Inheritance	Child classes inherit shared fields and can access base class data
Polymorphism	The same method call behaves differently depending on the item type
Constructors and Instances	Functional instances of each class can be created and used

Database and Queries

Deliverable	Description
Database File	A .db file is included in your repo with the correct tables and data
SQL Files	Schema and seed data SQL files are present in the database/ folder

Questions and Free Response

Deliverable	Description
Reflection	All reflection questions are answered in complete sentences

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Scoring Guide

Score	Description
4	All deliverables complete. Project is fully functional and the README clearly explains it.
3	All deliverables complete. Project works with minor issues.
2	Most deliverables complete. A few gaps in functionality or explanation.
1	Some deliverables complete. Significant gaps remain.
0	Little to no work submitted.

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Evidence of Testing

Include evidence of testing in your submission:

• A short section in this README (below) describing what you tested and what happened
• Seed data already in the database to show sample records
• Your completed tests/test_library.py with all tests passing

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Reflection Questions

Answer each question in 2–3 sentences. Write your answers directly in this README.

1. What is the role of LibraryItem as an abstract base class? Why is it useful to have one?

   • Answer:

2. What do the abstract methods (loan_duration_days, calculate_late_fee, details) force each child class to do? Why does this lead to better design?

   • Answer:

3. How does encapsulation (protected attributes + property setters with validation) protect your data? Give a specific example from the code.

   • Answer:

4. How does polymorphism appear in this project? Give an example of the same method call producing a different result depending on the object type.

   • Answer:

5. How is the database structured? What does each table store, and how do the tables relate to each other?

   • Answer:

6. What was the most challenging part of this project for you, and how did you work through it?

   • Answer:

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Testing Evidence

Replace this section with your own notes after you test the application.

Tested scenarios:

• Adding a book, DVD, and magazine
• Searching by title
• Checking out an item
• Returning an item (on time and late)
• Viewing overdue items