Steps to Implement Set Mapping in JPA

Here are the steps to implement the Set mapping.

Step 1: Define the entities

We can define the entities and it establish the one-to-many relationship using the @OneToMany annotation of the application.

@Entity
public class Parent {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL)
    private Set<Child> children;

    // Getters and setters
}

Step 2: We can use the @JoinColumn annotation to the specify the foreign key column in the child entity of the application.

@Entity
public class Child {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "parent_id")
    private Parent parent;

    // Getters and setters
}

Step 3: We can access and manipulate the associated entities through the Set collection in the parent entity of the application.

In Java, JPA is defined as Java Persistence API. The mapping association between the entities is an important aspect of designing database-driven applications. One such mapping is the Set mapping. It establishes the one-to-many relationship between the entities.

Set mapping in JPA is used to represent the collection of related entities where each entity instance can occur at the most in the collection.