can't insert a collection of elemenets

rhernando · **Joined:** Wed Mar 04, 2009 11:22 am **Posts:** 6

Hello,
I have a problem usin annotations. I have one entity (EntA):

Code:

@Entity
@Table(name = "ENT_A")
public class EntA implements Serializable {
...

@Id
public Long getOid() {
      return oid;
   }


[b]@CollectionOfElements(targetElement = EntB.class)
   @JoinTable(name = "ENT_B", joinColumns = @JoinColumn(name = "OID_ENT_A"))
   @MapKey(columns = @Column(name = "CODENTB"))
   public Map<String, EntB > getEntb() {
      return this.entB;
   }[/b]
...

And it have a collection of EntB:

Code:

@Entity
@Table(name = "ENT_B")
@IdClass(EntBPK.class)
public class EntB implements Serializable {
   @Id
   public Long getOidEntA() {
      return oidEntA;
   }

   @Id
   public String getCodEntB() {
      return codEntB;
   }

   @Column(name = "IMP_PART")
   public BigDecimal getImpPart() {
      return impPart;
   }

...
}

This class uses yhis PK:

Code:

public class EntBPK  implements Serializable {

   @Column (name = "OID_ENTA")
   public Long getOidEntA() {
      return oidEntA;
   }

   @Column
   public String getCodEntB() {
      return codPartida;
   }
}

When I try to insert EntityA with save(), there is a problem with entitiB. EntityA saves OK, but EntityB throws errors. In the log of hibernate I see this:

Quote:

Hibernate: insert into ENT_B (OID_ENT_A, CODENTB, entB_OID_ENT_B, entB_codEntB) values (?, ?, ?, ?)

those last fields in insert statement doesn't exists, so Oracle throws an error.

I don't know if I have any mistake with my annotations, but I have tried many things and I couldn't find anything

can anybody see anything wrong?

thanks in advance

R.Hernando

mmerder · **Posted:** Wed Mar 04, 2009 12:16 pm

The problem is, that you use "ENT_B" as Join-Table and as Table for class EntB.

If you don't want to use a seperate JoinTable map it like this:

Code:

    @OneToMany
    @JoinColumn(name = "OID_ENT_A")
    @MapKey(columns=@Column(name="CODENTB"))
    public Map<String, EntB > getEntb() {
      return this.entB;
    }

rhernando · **Joined:** Wed Mar 04, 2009 11:22 am **Posts:** 6

ok, I changed it.

Now the problem is that it doesn't make insert. it does one update for each row.
I think it's trying to change only its PK

Quote:

Hibernate: update ENT_B set OID_ENT_A=?, CODENTB=? where OID_ENT_A=? and codEntA=?

But those rows haven't been inserted yet.

then I tried with @Cascade.ALL and I have a different error. It's before inserting EntA:

log:

Quote:

Hibernate: select SEQ_ENT_A.nextval from dual
Hibernate: select entb_.OID_ENT_A, entb_.codEntB, entb_.IMPPART as IMPPART4_ from ENT_B entb_ where entb_.OID_ENT_A=? and entb_.codEntB=?

error:

Quote:

org.springframework.orm.hibernate3.HibernateSystemException: a different object with the same identifier value was already associated with the session:

Now I supossed that it's trying to find a row of Entb before inserting EntA

mmerder · **Posted:** Wed Mar 04, 2009 12:51 pm

I don't really understand your mapping or your kind of association. Do you really want to have the Id's of EntB as JoinColumns and value-columns for your map?
If not try just different names:

Code:

@OneToMany
    @JoinColumn(name = "EntAJoinColumn")
    @MapKey(columns=@Column(name="EntAMapKey"))
    public Map<String, EntB > getEntb() {
      return this.entB;
    } 

rhernando · **Joined:** Wed Mar 04, 2009 11:22 am **Posts:** 6

I'll show my schema:

table ENT_A (Long oid // PK, ...)

table ENT_B (Long oid_ent_a, // foreign key
String codentb,
Bigdecimal impart,...)

I can't use another MapKey, because the unique key with a OID is in entB.

I changed here the names of my app to make it more understandable, if you mean that.

I tried to use Set instead of Map, but I got same result.

I have other table mapped, almost the same, but ENT_B has only three fields, so I could map it as a MAP<String, BigDecimal>, without using another mapped class, and it works fine.

thanks a lot for your time

mmerder · **Posted:** Wed Mar 04, 2009 5:23 pm

Does EntB not have a primary key? If it is oid_ent_A then you actually got a one-to-one association there.

rhernando · **Joined:** Wed Mar 04, 2009 11:22 am **Posts:** 6

EntB's primary key is the pair OID_ENT_A-codentB, so there is a one-to-many association.

for the moment I have to insert ENT_B making a loop after inserting ENT_A

mmerder · **Posted:** Thu Mar 05, 2009 4:25 am

Well, that's a strange case that you got there and I created a test just out of curiosity. This case works as you maybe want, but not if you cascade all operations (maybe its a bug, what do the others say?)

Code:

@Entity
public class Customer {
    private long id;
       
    private Map<String, MapToMany> toManyMap;

    @Id
    @GeneratedValue
    public long getId() {
        return id;
    }

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

    @OneToMany(mappedBy="id.customer")
    @MapKey(columns=@Column(name="mapKey"))
    //Does not work on merge
    //    @Cascade({CascadeType.ALL})
    //works
    @Cascade({CascadeType.DELETE, CascadeType.PERSIST})
    public Map<String, MapToMany> getToManyMap() {
        return toManyMap;
    }

    public void setToManyMap(Map<String, MapToMany> toManyMap) {
        this.toManyMap= toManyMap;
    }
}

Code:

@Entity
public class MapToMany {
    
    private MapToManyId id;

    private BigDecimal impPart;

    @EmbeddedId 
    public MapToManyId getId() {
        return id;
    }
    public void setId(MapToManyId id) {
        this.id = id;
    }
    

    @Column(name = "IMP_PART")
    public BigDecimal getImpPart() {
        return impPart;
    }
    public void setImpPart(BigDecimal impPart) {
        this.impPart = impPart;
    } 
}

Code:

@Embeddable
public class MapToManyId implements Serializable
{
    private Customer customer;    
    private String mapKey;
    
    @ManyToOne
//    @Column(name="customer_id")
    public Customer getCustomer() {
        return customer;
    }
    public void setCustomer(Customer customer) {
        this.customer = customer;
    }
    public String getMapKey() {
        return mapKey;
    }
    public void setMapKey(String mapKey) {
        this.mapKey = mapKey;
    }
    
    
}

Testclass:

Code:

public class TestMap {
    public static void main(String[] args) throws Exception {
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("TestUnit",
                Collections.EMPTY_MAP);
        EntityManager em = factory.createEntityManager();
        Session s = (Session) em.getDelegate();
        em.getTransaction().begin();
        
        Customer customer = em.find(Customer.class, 1L);
                
        if(customer == null)
        {
            fillTables(em);
            em.clear();
            customer = em.find(Customer.class, 1L);
        }

        System.out.println(customer.getToManyMap().size());

        em.clear();
        System.out.println("----Cleared-----");

        //causes exception, if cascaded
        em.merge(customer);
        
        em.flush();

        em.getTransaction().commit();
    }
    
    private static void fillTables(EntityManager em)
    {
        Customer customer = new Customer();
        customer.setToManyMap(new HashMap<String, MapToMany>());
        
        MapToMany mk = new MapToMany();
        MapToManyId id = new MapToManyId();
        id.setCustomer(customer);
        id.setMapKey("key");
        mk.setId(id);
        mk.setImpPart(new BigDecimal(12));
        customer.getToManyMap().put(id.getMapKey(), mk);
        
        em.persist(customer);
        em.flush();
        System.out.println("-----------Finished Inserting---------");
    }
}

So, if you map it like this, you maybe get it working (rating is welcome, then ;-)).

But I am interested in what the others say. Is it a bug, that it does not work (infinite recursion) when merge is cascaded?

rhernando · **Joined:** Wed Mar 04, 2009 11:22 am **Posts:** 6

:)
it works!

I've changed mapping and now it inserts/deletes Ok.
It's curious, but putting @Cascade({CascadeType.DELETE, CascadeType.PERSIST}) does not insert my collection (because I'm inserting objects with save(Obj)), and I tried to put Cascade.all and works fine.

thanks a lot, mmerder

regards,
R.Hernando

mmerder · **Posted:** Thu Mar 05, 2009 9:52 am

CascadeType.SAVE_UPDATE would probably have helped you. Don't you get errors when merging objects of EntA (with an initialized EntB map)?

rhernando · **Joined:** Wed Mar 04, 2009 11:22 am **Posts:** 6

I need cascade to save and delete, so I'm using all. is it better to use only the types i will use?

I didn't have any error saving objects ( entA whit a full collection of entB). I don't understand exactly what you mean.