Spring Data JPA save child without fetch the parent

Question

How to save child entity with Spring data JPA repositories if you know the parent Id?

@Entity
public class Customer {
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;
    private String firstName;
    private String lastName;
    @ManyToOne
    private CustomerCategory category;
}

@Entity
public class CustomerCategory {
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;
    private String name;
}

Answer 1

Forget Id. You are now at the Object level of ORM (ObjectRelationMapping). Objects are composed of other objects. NO IDs.

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