Library Management System (ASP.NET Core Web API + EF Core + SQL Server)

Final Backend Training Project developed as part of ENG4YOU program.
This Web API application is built with ASP.NET Core, Entity Framework Core, and SQL Server, following OOP principles and clean architecture using the Controller-Service-Repository pattern for maintainability and scalability.

Awarded 1st place as one of the top 3 projects

Project Overview

The system manages a library’s core operations — users, books, categories, authors, and borrowing/returning processes — all through RESTful APIs.
It also implements role-based access, JWT authentication, FluentValidation, and a global exception handler.

Database Schema (SQL Server)

Table	Columns	Description
Book	Id (PK, INT), Title (NVARCHAR(256)), Isbn (NVARCHAR(20), Unique), CategoryId (FK), PublicationYear (INT), Description (NVARCHAR(MAX), nullable), CoverImageUrl (NVARCHAR(512), nullable)	Stores book details
Category	Id (PK, INT), Name (NVARCHAR(100), Unique)	Book categories
Author	Id (PK, INT), Name (NVARCHAR(200))	Authors of books
BookAuthors	BookId (FK), AuthorId (FK)	Many-to-many relationship between books and authors
Borrow	Id (PK, INT), UserId (FK), BookId (FK), BorrowedAt (DATETIME2), DueAt (DATETIME2), ReturnedAt (DATETIME2, nullable), Status (NVARCHAR(20) — Borrowed/Returned/Overdue)	Tracks borrowing history

Entity Relationships

• Book & Author: Many-to-Many
• Book & Category: Many-to-One
• User & Borrow: One-to-Many
• Book & Borrow: Many-to-One

API Endpoints

User Management

Method	Endpoint	Description	Roles
POST	/api/users/register-admin	Register a new admin	ADMIN
POST	/api/users/register-member	Register a new member	Public
POST	/api/users/register-librarian	Register a new librarian	ADMIN
POST	/api/users/login	Authenticate a user	Public
GET	/api/users/profile	Get user profile	MEMBER, ADMIN, LIBRARIAN
PUT	/api/users/profile	Update user profile	MEMBER, ADMIN, LIBRARIAN
POST	/api/users/profile-image	Set user profile image	MEMBER, ADMIN, LIBRARIAN

Book Management

Method	Endpoint	Description	Roles
GET	/api/books	Get all books	MEMBER, ADMIN, LIBRARIAN
GET	/api/books/{id}	Get book by ID	MEMBER, ADMIN, LIBRARIAN
POST	/api/books	Create a new book	ADMIN, LIBRARIAN
PUT	/api/books/{id}	Update a book	ADMIN, LIBRARIAN
DELETE	/api/books/{id}	Delete a book	ADMIN, LIBRARIAN
POST	/api/books/{id}/images	Set book images	ADMIN, LIBRARIAN

Category Management

Method	Endpoint	Description	Roles
GET	/api/categories	Get all categories	MEMBER, ADMIN, LIBRARIAN
GET	/api/categories/{id}	Get category by ID	MEMBER, ADMIN, LIBRARIAN
POST	/api/categories	Create a new category	ADMIN, LIBRARIAN
PUT	/api/categories/{id}	Update a category	ADMIN, LIBRARIAN
DELETE	/api/categories/{id}	Delete a category	ADMIN, LIBRARIAN

Author Management

Method	Endpoint	Description	Roles
GET	/api/authors	Get all authors	MEMBER, ADMIN, LIBRARIAN
GET	/api/authors/{id}	Get author by ID	MEMBER, ADMIN, LIBRARIAN
POST	/api/authors	Create a new author	ADMIN, LIBRARIAN
PUT	/api/authors/{id}	Update an author	ADMIN, LIBRARIAN
DELETE	/api/authors/{id}	Delete an author	ADMIN, LIBRARIAN

Borrow Management

Method	Endpoint	Description	Roles
POST	/api/borrows	Borrow a book	MEMBER
GET	/api/borrows	Get all borrows	ADMIN, LIBRARIAN
GET	/api/borrows/{id}	Get borrow by ID	ADMIN, LIBRARIAN
GET	/api/borrows/user/{userId}	Get all borrows for a specific user	ADMIN, LIBRARIAN
PATCH	/api/borrows/{id}	Update borrow status	ADMIN, LIBRARIAN
DELETE	/api/borrows/{id}	Delete a borrow	ADMIN, LIBRARIAN

Features & Tools

• Fluent Validation for input checking
• Controller-Service-Repository pattern for clean architecture
• DTOs for Create, Update, and Return operations
• JWT for authentication
• EF Core for data handling and relational mapping
• SQL Server as database
• Global Exception Handler for robust API responses

Technologies Used

• ASP.NET Core Web API
• Entity Framework Core
• SQL Server
• JWT Authentication
• FluentValidation
• OOP (Object-Oriented Programming)

This project demonstrates professional backend development skills, clean API design, effective handling of relational data, and practical application of OOP principles, reflecting the hands-on experience gained as part of ENG4YOU training.