Multiple writable mappings exception in EclipseLink

Question

I have these tables:

Which my intention is : A user can be a company or a person but each one of them have something in common, as username which is the email and password, so I used the JPA Tools to generate the entities from the table which result on this:

public class User implements Serializable {     private static final long serialVersionUID = 1L;      @Id     @GeneratedValue(strategy=GenerationType.AUTO)     private int id;      private String email;      private String password;      private int reputation;      //bi-directional one-to-one association to Company     @OneToOne(mappedBy="user", cascade={CascadeType.ALL})     private Company company;      //bi-directional many-to-one association to Location     @OneToMany(mappedBy="user")     private List<Location> locations;      //bi-directional one-to-one association to Person     @OneToOne(mappedBy="user")     private Person person;      //bi-directional many-to-one association to Product     @OneToMany(mappedBy="user")     private List<Product> products;      //bi-directional many-to-one association to UserType     @ManyToOne     @JoinColumn(name="type")     private UserType userType;      //bi-directional many-to-one association to UserPhone     @OneToMany(mappedBy="user")     private List<UserPhone> userPhones;      //bi-directional many-to-one association to UserPicture     @OneToMany(mappedBy="user")     private List<UserPicture> userPictures;      //bi-directional many-to-one association to UserSocialNetwork     @OneToMany(mappedBy="user")     private List<UserSocialNetwork> userSocialNetworks;          // getter and setters  } 

Now if I try to persist an user object launchs the follow exception in EclipseLink:

Exception [EclipseLink-48] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DescriptorException Exception Description: Multiple writable mappings exist for the field [COMPANY.id_user].  Only one may be defined as writable, all others must be specified read-only. Mapping: org.eclipse.persistence.mappings.OneToOneMapping[user] Descriptor: RelationalDescriptor(entity.Company --> [DatabaseTable(COMPANY)]) Exception [EclipseLink-48] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DescriptorException Exception Description: Multiple writable mappings exist for the field [PERSON.id_user].  Only one may be defined as writable, all others must be specified read-only. Mapping: org.eclipse.persistence.mappings.OneToOneMapping[user] Descriptor: RelationalDescriptor(entity.Person --> [DatabaseTable(PERSON)]) Runtime Exceptions:  

Is the generated mapping wrong ? How can I solve this exception ?

Update

public class Company implements Serializable {     private static final long serialVersionUID = 1L;      @Id     @GeneratedValue(strategy=GenerationType.AUTO)     @Column(name="id_user")     private int idUser;      private String email;      private String name;      //bi-directional many-to-one association to Area     @ManyToOne     @JoinColumn(name="area")     private Area areaBean;      //bi-directional one-to-one association to User     @OneToOne(cascade={CascadeType.ALL})     @JoinColumn(name="id_user", insertable=false, updatable=false)     private User user;          // getter and setters }  @Entity public class Person implements Serializable {     private static final long serialVersionUID = 1L;      @Id     @GeneratedValue(strategy=GenerationType.AUTO)     @Column(name="id_user")     private int idUser;      @Temporal( TemporalType.DATE)     private Date birthdate;      private String gender;      private String name;      private String surname;      //bi-directional one-to-one association to User     @OneToOne     @JoinColumn(name="id_user", insertable=false, updatable=false)     private User user;          // getters and setters } 

Answer 1

The proper way to do this is to use @PrimaryKeyJoinColumn instead of plain old @JoinColumn.

reference wiki example on PrimaryKeyJoinColumn

Answer 2

I solved my problem placing the insertable=false, updatable=false in the @JoinColumn annotation in both classes, Person and Company.