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/Class Diagram for the Library Management System
Class Diagram for the Library Management System
Understand how to create a class diagram for a library management system by using the bottom-up approach.
We'll cover the following...
Here, we’ll create the class diagram for our system based on the previously gathered requirements. In the class diagram, we will first design/create the classes, abstract classes, and interfaces for the system, and then we’ll identify the relationship between classes in accordance with all requirements of the library management system.
Components of a library management system
In this section, we will define the classes for LMS. Following the bottom-up approach for designing a class diagram, we’ll first create the classes of small components. After that, we will integrate those components and create the class diagram for the library management system.
Book and book item
The Book class represents the conceptual essence of a book. This includes metadata or descriptive information about a book that isn’t specific to any physical copy. It serves as a blueprint that captures the shared attributes of all instances or copies of the book, whether in the world or within the library’s collection.
The BookItem class, in contrast, represents a specific physical or digital instance of a Book in the library’s collection. Rather than extending the Book, it has a composition relationship with it, meaning each BookItem is tightly associated with a Book. All corresponding BookItem instances must also be deleted if a Book is deleted. The BookItem class handles the properties and behaviors associated with individual copies that patrons can borrow, reserve, or reference within the library. Each BookItem has unique attributes to manage and track its status within the library system. The UML representation of Book and BookItem is shown in the class diagram below:
Rack
We have seen a complex object, Rack, that was defined in the BookItem class. Now, we are going to create a Rack class. This class is used to identify the physical location of any book item in the library. Every rack has a specific rack number and a location identifier to represent the location of the book item in the library. The visual representation of the class is as follows:
Person and author
The Person class stores information related to a person, such as a name, email, phone number, etc. It also contains an object of the Address class to specify the person’s address.
There is also a class named Author that stores the author’s data, such as the author’s name and description. The author’s information is also used in the Book class.
The representation of both classes is as follows:
