[FIXED] JPA OneToOne association without foreign key always fail

Issue

I am new to JPA/Hibernate, I am creating a simple join for getting some data in different table Let's see like this:

src="https://i.stack.imgur.com/vVJ1b.png" alt="enter image description here">

The purpose is getting the M_PROFILE data based on M_USER.username column, but clearly you see that there is no foreign key in M_PROFILE table.

I just try to use below code but have no results and always got error.

User Entity Class

@Entity
@Table(name = "M_USER")
public class User {

        @Id
        @Column(name = "id")
        private String uuid;

        @Column(name = "email")
        private String email;

        @Column(name = "username")
        private String username;

        @OneToOne(fetch = FetchType.LAZY)
        @MapsId("username")
        private Profile profile;

        public String getId() {
            return id;
        }
        public void setId(String id) {
            this.id = id;
        }

        public String getEmail() {
            return email;
        }
        public void setEmail(String email) {
            this.email = email;
        }

        public String getUsername() {
            return username;
        }
        public void setUsername(String username) {
            this.username = username;
        }

        public Profile getProfile() {
            return profile;
        }
        public void setProfile(Profile profile) {
            this.profile = profile;
        }
    }

Profile Entity Class

@Entity
@Table(name = "M_PROFILE")
public class Profile {

    private String username;
    private String phone;
    private String address;

    @Id
    @Column(name = "username", nullable = false)
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Basic
    @Column(name = "phone")
    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    @Basic
    @Column(name = "address")
    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

I got different error when calling

User user = userRepository.findByUsername("aswzen");
String phone = user.getProfile().getPhone();

for example this one.

"USER0_"."PROFILE_USERNAME": invalid identifier

Need help, thanks in advance,

NB : i don't have privilege to alter the table..

Solution

Try to specify a join column:

@OneToOne
@JoinColumn(name = "username", referencedColumnName = "username")
private profile profile;

You do not really need the @MapsId here.

Answered By - Maciej Kowalski
Answer Checked By - Willingham (JavaFixing Volunteer)