Column mapping with @Column in Spring Boot - Mini Project: Build & Apply

Column mapping with @Column in Spring Boot

📖 Scenario: You are building a simple Spring Boot application to manage books in a library. Each book has a title and a number of pages. You want to map these fields to specific columns in a database table using the @Column annotation.

🎯 Goal: Create a Spring Boot entity class called Book with fields title and pages. Use the @Column annotation to map title to a database column named book_title and pages to a column named number_of_pages.

📋 What You'll Learn

Create a class named Book annotated with @Entity

Add a private field title of type String

Add a private field pages of type int

Use @Column(name = "book_title") on the title field

Use @Column(name = "number_of_pages") on the pages field

💡 Why This Matters

🌍 Real World

Mapping Java class fields to database columns is essential when working with databases in Spring Boot applications. It ensures your data is stored and retrieved correctly.

💼 Career

Understanding @Column mapping is a basic skill for Java developers working with Spring Boot and JPA for database operations.

1

Create the Book entity class with fields

Create a public class called Book and add two private fields: title of type String and pages of type int.

Spring Boot

public class Book {
    // Your code here
}

Need a hint?

Think of the Book class as a blueprint for book objects. Add the fields inside the class.

2

Add @Entity annotation to the Book class

Add the @Entity annotation above the Book class declaration to mark it as a JPA entity.

Spring Boot

@Entity
public class Book {
    private String title;
    private int pages;
    // Your code here
}

Need a hint?

The @Entity annotation tells Spring Boot this class maps to a database table.

3

Map the title field to book_title column

Add the @Column(name = "book_title") annotation above the title field to map it to the database column named book_title.

Spring Boot

@Entity
public class Book {
    @Column(name = "book_title")
    private String title;
    private int pages;
    // Your code here
}

Need a hint?

The @Column annotation lets you specify the exact database column name for a field.

4

Map the pages field to number_of_pages column

Add the @Column(name = "number_of_pages") annotation above the pages field to map it to the database column named number_of_pages.

Spring Boot

@Entity
public class Book {
    @Column(name = "book_title")
    private String title;
    @Column(name = "number_of_pages")
    private int pages;
    // Your code here
}

Need a hint?

Just like the title, use @Column to map the pages field to the correct column.