Design Library Management System
Design a Library Management System that allows users to search, borrow, and return books using object-oriented design.
A Library Management System is software used to manage the operations of a library, such as tracking books, managing inventory, handling book checkouts and returns, maintaining user records, and enforcing due dates and fines.
It helps librarians and users efficiently organize and access library resources.
In this chapter, we will explore the low-level design of a library management system in detail.
Lets start by clarifying the requirements:
1. Clarifying Requirements
Before starting the design, it's important to ask thoughtful questions to uncover hidden assumptions and better define the scope of the system.
Here is an example of how a conversation between the candidate and the interviewer might unfold:
Candidate: Can a book have multiple copies, and should each copy be tracked individually?
Interviewer: Yes, a book can have multiple copies, and each copy should be treated as a separate entity
Candidate: Should we support different user roles, such as librarian and members, with different permissions?
Interviewer: Yes. Librarians can manage the book inventory, issue/return books, and handle user accounts. Members can search for books, borrow them, and view their own history.
Candidate: Do we need to enforce borrowing limits, such as maximum books per user or due dates for returns?
Interviewer: Yes, each member should be allowed to borrow up to a fixed number of books (say 5), and each book should have a due date, after which fines can be applied.
Candidate: Should the system support searching and filtering books by title, author, genre, etc.?
Interviewer: Yes, the system should allow users to search and filter books using various criteria such as title, author, genre, or ISBN.
Candidate: Should we maintain a borrowing history for each member?
Interviewer: Yes, the system should maintain borrowing and return history for every member for tracking purpose.
After gathering the details, we can summarize the key system requirements.
1.1 Functional Requirements
- Support user registration with different roles (librarian, member)
- Allow librarians to add, update, and remove books from the catalog.
- Track multiple physical copies of the same book as separate entities.
- Librarians can manage the book catalog and issue/return books
- Members can borrow and return books
- Enable members to search for books by title, author, and ISBN.
- Limit maximum active borrowed books per user and due dates.
- Fines should be calculated for overdue returns.
- Maintain a transaction log for all borrow and return activities
1.2 Non-Functional Requirements
- Modularity: The system should follow object-oriented principles with clear separation between modules like user management and catalog management
- Extensibility: The design should be easy to extend to support future features
- Maintainability: The system should be easy to test, debug, and enhance over time
After the requirements are clear, lets identify the core entities/objects we will have in our system.