ManyToMany or OneToOne?

Question

Java

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

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

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

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

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

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

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

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

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

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

    @Transient
    private String confirmPassword;

    @ManyToMany
    @JoinTable(name = "user_roles", joinColumns = @JoinColumn(name = "user_id"),
            inverseJoinColumns = @JoinColumn(name = "role_id"))
    Set<Role> roles;

    public User() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getLogin() {
        return login;
    }

    public void setLogin(String login) {
        this.login = login;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    public String getAvatar() {
        return avatar;
    }

    public void setAvatar(String avatar) {
        this.avatar = avatar;
    }

    public String getEmail() {
        return email;
    }

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

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getConfirmPassword() {
        return confirmPassword;
    }

    public void setConfirmPassword(String confirmPassword) {
        this.confirmPassword = confirmPassword;
    }

    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

    public String getFlag() {
        return flag;
    }

    public void setFlag(String flag) {
        this.flag = flag;
    }

    public String getKey_token() {
        return key_token;
    }

    public void setKey_token(String key_token) {
        this.key_token = key_token;
    }
}

this is POJO User, the question is whether it is necessary to do ManyToMany when there is only one role for the user?

Answer 1

If there is only one role, then why do you need many? Doing 1-1