Question

I currently work on a web app using Java EE/EclipseLink and postgreSQL.
About my entities, I manage in particular “Project” , “User” and “Right” (access rights like read, write, delete…). The relationship between these entities is : a project can have multiple users who have different rights on the project. Hence, I get a triple association: Project+User+Right.

I’m facing an annoying problem during this association’s persistence. When I persist a project with its information, everything is fine (it’s in the DB and I can use it in my app), I also have persisted rights and users. Then, I want to add an association between them so I create the association entity called ProjectUserRight, I set the project, the user and the right from existing entities but when I persist it, I get the exception below :

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERREUR: une valeur NULL viole la contrainte NOT NULL de la colonne « id_project »
Error Code: 0
Call: INSERT INTO project_user_right (id_right, id_project, id_user) VALUES (?, ?, ?)
bind => [3 parameters bound]
Query: InsertObjectQuery(ProjectUserRight@192db555)

Here is the class Project :

@Entity
@Table(name="project")
public class Project implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_project", unique=true, nullable=false)
private Integer idProject;


   //bi-directional many-to-one association to ProjectUserRight
@OneToMany(mappedBy="project", cascade={CascadeType.ALL})
private Set<ProjectUserRight> projetUtilDroits;


  ...

The class User :

 @Entity
 @Table(name="user")
 public class User implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_user", unique=true, nullable=false)
private Integer idUser;


@Column(name="nom_utilisateur", nullable=false, length=50)
private String userName;

   //bi-directional many-to-one association to ProjectUserRight
@OneToMany(mappedBy="user")
private Set<ProjectUserRight> projetUtilDroits;

   ...

The class Right :

   @Entity
   @Table(name="right")
   public class Right implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_right", unique=true, nullable=false)
private Integer idRight;

@Column(name="type_right", nullable=false, length=10)
private String typeRight;

//bi-directional many-to-one association to ProjectUserRight
@OneToMany(mappedBy="right")
private Set<ProjectUserRight> projetUtilDroits;

    ...

And the association class :

 @Entity
 @Table(name="project_user_right")
 public class ProjectUserRight implements Serializable {
private static final long serialVersionUID = 1L;

@EmbeddedId
private ProjectUserRightPK id;

//bi-directional many-to-one association to Right
    @ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH})
@JoinColumn(name="id_right", insertable=false, updatable=false)
private Right right;

//bi-directional many-to-one association to Project
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH})
@JoinColumn(name="id_project", insertable=false, updatable=false)
private Project project;

//bi-directional many-to-one association to User
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH})
@JoinColumn(name="id_user", insertable=false, updatable=false)
private User user;

And the ProjectUserRightPK (edited after comment) :

@Embeddable
public class ProjectUserRightPK implements Serializable {
//default serial version id, required for serializable classes.
private static final long serialVersionUID = 1L;

@Column(name="id_project", unique=true, nullable=false)
private Integer idProject;

@Column(name="id_right", unique=true, nullable=false)
private Integer idRight;
    ...//getters and setters
@Column(name="id_user", unique=true, nullable=false)
private Integer idUser;

I wrote the following code to persist the association:

 Project project = getService(Projet.class).getFromID(projectId);//retrieve the existing project from database with id

 User user = getService(Utilisateur.class).getFromID(userId);//retrieve the existing user from database with id

 Right right = getService(Right.class).getFromID(rightId);//retrieve the existing right from database with id
 if(project !=null && user!=null && right!=null){
   ProjectUserRight pud = new ProjectUserRight();
   pud.setRight(right);
   pud.setProject(project);
   pud.setUser(user);
   project.getProjectUserRights().add(pud);
   right.getProjectUserRights().add(pud);
   user.getProjectUserRights().add(pud);
   service(ProjetUtilDroit.class).persist(pud);//call the persist function on this entity (works fine with all other entities)
   }

I also tried to merge the project instead of persisting the association but I get the same error… (I also checked the id project and it is properly set) I’m wondering if it’s the association which is wrongly annotated but I can’t find the proper way to change it.

So, I really need your help! 🙂

Thanks in advance for your advice!

Answer 1

You missed the @MapsId annotation:

Designates a ManyToOne or OneToOne relationship attribute that
provides the mapping for an EmbeddedId primary key, an attribute
within an EmbeddedId primary key, or a simple primary key of the
parent entity. The value element specifies the attribute within a
composite key to which the relationship attribute corresponds.

@MapsId("idRight")
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH})
@JoinColumn(name="id_right")
private Right right;

@MapsId("idProject")
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH})
@JoinColumn(name="id_project")
private Project project;

@MapsId("idUser")
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH})
@JoinColumn(name="id_user")
private User user;