primarykey mapping problem

[jzmmek2k2]

I have got a question about primarykey-mapping.

Having two tables:

t_customer
---------------
int | customer_id (PK)
varchar | firstname
varchar | lastname

t_friendship
---------------
int | customer_id (PK)
int | friend_customer_id (PK)
date | created


Is it possible to map this two tables to the following class-structure using annotations ?

class Customer
{
public Long getId() {...}
public String getFirstname() {...}
public String getLastname() {...}
}

class Friendship
{
public Customer getCustomer() {...}
public Customer getFriend() {...}
public Date getCreated() {...}
}


The "Customer"-class is not the problem, but I am simply unable to declare "getCustomer() & getFriend()" as compound primary-key of class "Friendship".


Any help would be appreciated

Regards
Jan

[bill.burke]

Use @IdClass

See Hibernate EntityManager doco or specification . I don't have an wxample of it in the tjutotirals Only @EmbeddedId

[jzmmek2k2]

Thanks for fast reply, but I still having problems get it working.


The following schema is generated

CREATE TABLE t_customer
(
 customer_id int8 NOT NULL,
 firstname varchar(255),
 lastname varchar(255),
 CONSTRAINT t_customer_pkey PRIMARY KEY (customer_id)
)
WITHOUT OIDS;

CREATE TABLE t_friendship
(
 customer bytea NOT NULL,
 friend bytea NOT NULL,
 created timestamp,
 CONSTRAINT t_friendship_pkey PRIMARY KEY (customer, friend)
)
WITHOUT OIDS;

When I deploy the following classes

@Entity
@Table(name="t_customer")
public class Customer implements Serializable
{
 private Long pk = null;
 private String firstname = null;
 private String lastname = null;

 public Customer2()
 {
 }

 public String getFirstname()
 {
 return firstname;
 }

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

 public String getLastname()
 {
 return lastname;
 }

 public void setLastname(String name2)
 {
 this.lastname = name2;
 }

 @Id
 @GeneratedValue(strategy=GenerationType.AUTO)
 @Column(name="customer_id")
 public Long getPk()
 {
 return pk;
 }

 public void setPk(Long pk)
 {
 this.pk = pk;
 }
}

@Embeddable
public class FriendshipPK implements Serializable
{
 private Customer customer = null;
 private Customer friend = null;

 public FriendshipPK()
 {
 }

 public Customer getCustomer()
 {
 return customer;
 }

 public void setCustomer(Customer customer)
 {
 this.customer = customer;
 }

 public Customer getFriend()
 {
 return friend;
 }

 public void setFriend(Customer friend)
 {
 this.friend = friend;
 }

}

@Entity
@Table(name="t_friendship")
@IdClass(FriendshipPK.class)
public class Friendship
{
 private Customer customer = null;
 private Customer friend = null;

 private Date created = null;

 public Friendship()
 {
 }

 public Date getCreated()
 {
 return created;
 }

 public void setCreated(Date created)
 {
 this.created = created;
 }

 @EmbeddedId
 public Customer getCustomer()
 {
 return customer;
 }

 public void setCustomer(Customer customer)
 {
 this.customer = customer;
 }

 @EmbeddedId
 public Customer getFriend()
 {
 return friend;
 }

 public void setFriend(Customer friend)
 {
 this.friend = friend;
 }
}

There is no difference when using "@Id" instead of "@EmbeddedId" in class "Friendship".


It always generates the columns "customer" & "friend" of type "byte" instead of "int8".


I am using EJB3 RC4-PFD.


Looking in the docs does not really help, because it always describes PK consisting of primitive types.


Would be great if anyone could help me.

Regards
Jan

[epbernard]

please reread the whole chapter about composite primary keys you're are mismatching all annotations.