component diagram for library management system PlantUML code ?

Sure! Below is the PlantUML code for a simple component diagram representing a Library Management System:

plantuml
@startuml LibraryManagementSystemComponentDiagram

!define ENTITY entity
!define CONTROL control

!define DATABASE database
!define STORAGE storage

!define LIBRARY_LIBRARY entity "Library"
!define BOOK_ENTITY entity "Book"
!define MEMBER_ENTITY entity "Member"
!define LOAN_ENTITY entity "Loan"

!define LIBRARY_CONTROLLER control "LibraryController"
!define BOOK_CONTROLLER control "BookController"
!define MEMBER_CONTROLLER control "MemberController"
!define LOAN_CONTROLLER control "LoanController"

!define DATABASE_SERVER database "Database Server"

!define DATA_STORAGE storage "Data Storage"

[LIBRARY_CONTROLLER] --> [LIBRARY_LIBRARY]
[BOOK_CONTROLLER] --> [BOOK_ENTITY]
[MEMBER_CONTROLLER] --> [MEMBER_ENTITY]
[LOAN_CONTROLLER] --> [LOAN_ENTITY]

[LIBRARY_CONTROLLER] --> [DATABASE_SERVER] : "Queries"
[BOOK_CONTROLLER] --> [DATABASE_SERVER] : "Queries"
[MEMBER_CONTROLLER] --> [DATABASE_SERVER] : "Queries"
[LOAN_CONTROLLER] --> [DATABASE_SERVER] : "Queries"

[DATABASE_SERVER] --> [DATA_STORAGE]

@enduml
```

In this component diagram, we have identified four main entities in the Library Management System: `Library`, `Book`, `Member`, and `Loan`. These entities represent the main components of the system that handle data related to books, library members, and book loans.

Additionally, we have identified four controllers: `LibraryController`, `BookController`, `MemberController`, and `LoanController`. These controllers represent the components responsible for handling the business logic and interaction between the user interface and the data entities.

The `Database Server` represents the component responsible for managing the database and handling queries from the controllers.

The `Data Storage` component represents the storage medium (e.g., a database or a file system) where the data for the Library Management System is stored.

Arrows connecting the controllers to their respective entities represent the interaction between the controllers and the data entities. The arrows connecting the controllers to the `Database Server` represent the queries made by the controllers to retrieve or update data from the database.

Note: This is a simplified representation of a Library Management System’s component diagram. In real-world scenarios, a more comprehensive diagram might include additional components, interfaces, and relationships.