Spring Boot/Hibernate: How to define one-to-one unidirectional relationship

Question

I have People entity that has name and parent where parent is a People .

@Entity
public class People {

    @Id
    private Long id;

    @Column
    @NotNull(message = "error.name.type.null")
    private String name;

    @OneToOne(cascade=CascadeType.ALL,fetch = FetchType.EAGER)
    private People parent;

    // getters and setters
}

When I store data using PUT , I specify the id 1 as a path variable and provide the name as data input and did not pass parent like:

curl -i -X PUT -H "Content-Type:application/json" -d '{"name":"John"}'

Response

http://localhost:8080/people/1
HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: Wed, 12 Oct 2016 13:51:52 GMT

When I retrieve what is stored, parent already have a link to the object itself although I passed null when making the curl request.

What am I doing wrong with the Hibernate One-to-One relationship?

curl -i -X GET http://localhost:8080/people
HTTP/1.1 200 
Content-Type: application/hal+json;charset=UTF-8
Transfer-Encoding: chunked
Date: Wed, 12 Oct 2016 13:53:10 GMT

{
  "_embedded" : {
    "people" : [ {
      "name" : "John",
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/people/1"
        },
        "people" : {
          "href" : "http://localhost:8080/people/1"
        },
        "parent" : {
          "href" : "http://localhost:8080/people/1/parent"
        }
      }
    } ]
  },
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people"
    },
    "profile" : {
      "href" : "http://localhost:8080/profile/people"
    },
    "search" : {
      "href" : "http://localhost:8080/people/search"
    }
  }
}

Answer 1

You're missing either @JoinColumn(name="parent_id") or @OneToOne(mappedBy="id", cascade=CascadeType.ALL,fetch = FetchType.EAGER)

From reading your code i think you want @JoinColumn .

See Hibernate self-referencing one-to-one relationship - mapped/owned side