Planned lessonJNR-028-L03

Embeddables and value objects

Lesson 3 of 8
Junior

On This Lesson 4 topics

In this lesson
Planned topics
Draft outline details
Practice

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

store a value object in the owner's table.

Planned topics

A value object has no identity of its own; Money is just amount plus currency.
@Embeddable marks the class; @Embedded uses it in an entity.
Its fields become columns of the owner's table (granularity solved).
Rename columns with @AttributeOverride if the same embeddable appears twice.
Make value objects immutable.

Draft outline details

Demonstration

java

@Embeddable
public record Money(
    @Column(name = "price_amount") BigDecimal amount,
    @Column(name = "price_currency", length = 3) String currency) {}

// in Product:
@Embedded private Money price;

Check your understanding

Does an embeddable get its own table?

Show answer

No; its columns live in the owner's table.

Practice

Apply this lesson with the module's lab, exercises and quiz.

Lab and exercises Quiz

Marking a lesson complete is optional and you can undo it any time. Your progress stays in this browser.

Continue to next lesson