Model with Hibernate to Query by Contact Details in Spring Boot

Question

I would like to be able to query for an employee by the contact details. Here is my model.

You can assume that I have the controller working.

public abstract class BaseEntity implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    public boolean isNew() {
        return this.id == null;
    }
}

public abstract class PersonalInformation extends BaseEntity {
    @Temporal(TemporalType.DATE)
    private Date dateOfBirth;
    private String gender;
}


public abstract class Person extends PersonalInformation implements Serializable {

    private String firstName;
    private String lastName;
    private String middleName;
    private String alias;

    @Temporal(TemporalType.DATE)
    private Date dateOfBirth;
    private String gender;

    @OneToOne(cascade = CascadeType.ALL)
    private Contact contact;

}

public class Owner extends Person implements Serializable {
}

public class Contact extends BaseEntity {
    private String emailAddress;
    private String mobileTelNo;
    private String homeTelNo;
    private String workTelNo;
}

This is what I tried, thinking that the persistence will be both ways, wo when I would build a controller, I could build the response to include either the owner or the employee or other entity that I might have in my system of contacts

public class Contact extends BaseEntity {
    private String emailAddress;
    private String mobileTelNo;
    private String homeTelNo;
    private String workTelNo;
    
    @OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    private Owner owner;
    
    @OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    private Employee employee;
}

The relation between contact and owner or any other entity that would have a contact is one to one.

Could someone help me map my entities one to another, so that data is persisted? Is what I want to do a good practice, or is there a better way?

Desired output when querying by the email:

GET: http://localhost:8080/v1/contact/email/jow.doe@stackoverflow.com

{
              "firstName": "Joe",
              "lastName": "Doe",
              "middleName": "None",
              "alias": "JD",
              "dateOfBirth": "2000-02-12",
              "gender": "male",
              "contact": {
                  "emailAddress": "joe.doe@stackoverflow.com"

              }
          }

Note: please ignore if I missed any data in the output that is in the pojos.

Answer 1

IMO Contact should not have any mappings to Owner or Employee . If you don't need it, don't map it. You can query the data by using a HQL query like FROM Owner o JOIN o.contact c WHERE c.emailAddress =:email .