creating composite pk with foreign key

noone · **Joined:** Thu Sep 23, 2004 11:53 am **Posts:** 83

Hibernate version:3.0

Mapping documents:Annotation

class myclass
{
@Id(generate=GeneratorType.NONE)
private String myid;

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "myid_id")
private Collection<yourclass> yours;
}

class yourclass
{
@Id(generate=GeneratorType.AUTO)
private int id;

// how to make this part of the primary key?
@ManyToOne
@JoinColumn(name = "myid_id")
private myclass mine;
}

How can I make "mine" part of yourclass's primary key?

Thanks

emmanuel · **Posted:** Mon Feb 28, 2005 1:24 am

It's not officially supported yet, I thought it would work.
please provide a runnable test case and post it to JIRA in HibernateExt/Annotations
I'll have a look

noone · **Joined:** Thu Sep 23, 2004 11:53 am **Posts:** 83

Hmmm... did not know the below code should have created the yourclass primary key (id, myid_id). My question is how to create such a key? :)
Is the below code suppose to create the above mentioned key?

Thanks :)

emmanuel · **Posted:** Mon Feb 28, 2005 12:58 pm

forget what I've said.
You want to use a composite key wo a PK class. this not currently possible.

noone · **Joined:** Thu Sep 23, 2004 11:53 am **Posts:** 83

I have looked over the example for creating a PK class. Seems easy enough, but how do I add a foriegn key to the PK class? So at this piont I understand that I need PK class, what I do not understand is how to add the foreign key to th PK class. Example...

CREATE TABLE A (
VARCHAR name NOT NULL,
primary key(name)
)

CREATE TABLE B (
INT item NOT NULL,
foreign key (name),
primary key(name,item) // this is what I want to do in hibernate
)

Thanks :)

noone · **Joined:** Thu Sep 23, 2004 11:53 am **Posts:** 83

I looked at the dependent object example. I updated to try to make the foriegn parent pk part of the childs primary key. So, I still need help with this please....

SQL executed by Hibernate
12:41:43,953 DEBUG SchemaExport:154 - create table Parent (
firstName varchar2(255) not null,
lastName varchar2(255) not null,
age number(10,0),
primary key (firstName, lastName)
)
12:41:45,046 DEBUG SchemaExport:154 - create table Child (
firstName varchar2(255) not null,
lastName varchar2(255) not null,
parenFirstName varchar2(255) not null,
parentLastName varchar2(255) not null,
primary key (firstName, lastName)
)
12:41:45,109 DEBUG SchemaExport:154 - alter table Child add constraint FK3E104FC157CBEB0 foreign key (parenFirstName, parentLastName) references Parent
12:41:45,140 INFO SchemaExport:166 - schema export complete

Child pojo

Code:

@Entity(access = AccessType.FIELD)
public class Child implements Serializable {
    @Id(generate = GeneratorType.NONE)
    public ChildPk id;    
}

Child PK

Code:

@DependentObject(access = AccessType.FIELD)
public class ChildPk implements Serializable {
    String firstName;
    String lastName;

    @ManyToOne()
    @JoinColumns ({
            @JoinColumn(name="parentLastName", referencedColumnName = "lastName"),
            @JoinColumn(name="parenFirstName", referencedColumnName = "firstName")
    })  
    public Parent parent;
}

Parent PK

Code:

@Entity(access = AccessType.FIELD)
public class Parent implements Serializable {
    @Id
    public ParentPk id;
    public int age;

    @OneToMany(cascade=CascadeType.ALL)
    @JoinColumns ({
        @JoinColumn(name="parentLastName", referencedColumnName = "lastName"),
        @JoinColumn(name="parenFirstName", referencedColumnName = "firstName")
    })
    public Set<Child> children;
}

[/code]

emmanuel · **Posted:** Fri Mar 04, 2005 3:00 pm

I don't really get your sample, because I would have declare the many to one on the child class and not the child pk (as per your DDL). Anyway, here is the way you would declare a many to one inside a PK

Code:

@DependentObject(access=AccessType.FIELD)
public class ChildPk implements Serializable {
   public int nthChild;

   @ManyToOne()
   @JoinColumns ({
           @JoinColumn(name="parentLastName", referencedColumnName = "lastName"),
           @JoinColumn(name="parentFirstName", referencedColumnName = "firstName")
    })
   public Parent parent;

   public boolean equals(Object o) {
      //do it
   }

   public int hashCode() {
      //do it
   }
}

But it is not currently working on the annotation implementation (HBX-126) and 'll get hard time to make it work.