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Question

Splitting Hibernate Entity among 2 Tables

Answer 1

+1 A:

From the exception you posted, it appears as if the table has not yet been created in your database ("Table MOVEMENT_DATA not found"). If you have not instructed Hibernate/JPA to alter your schema you have to manually add the table prior to running your code (I believe it is CREATE-UPDATE to instruct hibernate to perform the alter's).

Rich Kroll 2009-04-28 18:28:18

I already have that in my persistence.xml

Grasper 2009-04-28 19:10:11

Answer 2

+1 A:

During development its often convenient to have this property enabled:

cfg.setProperty(Environment.HBM2DDL_AUTO, "update");

where cfg is my AnnotationConfiguration.

Your problem will most likely be solved by enabling this property.

Schildmeijer 2009-04-29 13:57:51

I have create-drop set (see my persistence.xml above). I just tried it with update instead, and it still doesn't work with the same error.

Grasper 2009-04-29 20:00:39

NOTE for anyone else with this problem: Answer was Auto Selected... This doesn't work.

Grasper 2009-05-07 20:42:09

Answer 3

A:

Definition of embeddable class should not reference database table:

@Embeddable
public class MovementData implements Serializable {


    private double speed;
    private Date timeOfPosition;
    private double latitude;
    private double longitude;
    private static final long serialVersionUID = 1L;

    public MovementData() {
        super();
    }   

    @Column(name="SPEED")
    public double getSpeed() {
        return this.speed;
    }

    ...

    @Column(name="TIME_OF_POSITION")
    public Date getTimeOfPosition() {
        return this.timeOfPosition;
    }

    ...

    @Column(name="LONGITUDE")
    public double getLongitude() {
        return this.longitude;
    }

    ...

    @Column(name="LATITUDE")
    public double getLatitude() {
        return this.latitude;
    }

    ...
}

Then Vehicle entity should define secondary table for embedded structure including join column:

@Entity
@Table(name="VEHICLE")
@Inheritance(strategy=InheritanceType.JOINED)
@SecondaryTable(name="MOVEMENT_DATA",
                pkJoinColumns = {
                    @PrimaryKeyJoinColumn(name = "ID") 
                } 
)
public class Vehicle implements Serializable {


    private int numWheels;
    private String color;
    private int id;
    private MovementData movementData;
    private static final long serialVersionUID = 1L;


    public Vehicle() {
        super();
    }   

    @Embedded
    @AttributeOverrides( {
        @AttributeOverride(
            name = "speed",
            column = @Column(name = "SPEED",
                             table = "MOVEMENT_DATA")
        ),
        @AttributeOverride(
            name = "timeOfPosition",
            column = @Column(name = "TIME_OF_POSITION",
                             table = "MOVEMENT_DATA")
        ),

        ... // override the rest of the attributes

    } )
    public MovementData getMovementData() {
        return movementData;
    }

    ...

    @Id    
    public int getId() {
        return this.id;
    }

    ...
}

I hope this will work for you.

grigory 2009-05-02 04:30:41

Thanks for the help... Still get the same error though. I am at my wits end!

Grasper 2009-05-02 16:47:33

When I run into problems like this I try to simplify playing field to make it as transparent as possible. In this case I'd take out inheritance setup from the Vehicle entity - that way you deal with one problem at the time (hopefully). After you solve problem of embeddable object in a secondary table then roll inheritance back and see how they work together.

grigory 2009-05-02 20:34:47

Answer 4

+1 A:

I would try breaking this down to find the issue. Try making movement data into an entity instead of an embeddable class. Make sure that it can stand on its own and then change it back to embeddable.

Although its not really the relationship that you want, you might try making MovementData the root parent and have Vehicle inherit off of MovementData. That way you would only be working with

@Inheritance(strategy=InheritanceType.JOINED)

instead of inheritance plus secondaryTable. It would simplify the relationship but still include all of the tables.

ccclark 2009-05-04 14:01:57

Ah.. I think you are right.. It may be an issue with mixing @SecondaryTable with the joined Inheritance Strategy, since, from a DB perspective they look the same. This is not really an ideal solution, as I want my Java Entities to look as above.

Grasper 2009-05-04 17:45:07

So you could also make it not a secondary table but just a OneToOne relationship between Vehicle and MovementData. With the right cascades it would behave the same.

ccclark 2009-05-04 20:27:30

Answer 5

A:

Connect to your database using your appropriate db client (Query Browser, MS SQL Managment Studio, etc) to verify whether or not the tables do, in fact, exist.

You may also want to insert a breakpoint in your code so that you can see exactly what the database looks like at the moment before it's throwing this error.

Try setting the hibernate.hbm2ddl.auto value to "create" as below, and also change the setting so that it prints out the SQL so you can see what it's attempting:

<props>
  <!-- some possible values: create, create-drop, update -->
  <prop key="hibernate.hbm2ddl.auto">update</prop>
  <prop key="hibernate.show_sql">true</prop>
  ....
<props>

Let me know what you see in your db.

Cuga 2009-05-06 14:22:15

It ends up not creating anything in the actual DB when I set that to create. It throws that exception before that point. I added some more of the logging info to my post above.

Grasper 2009-05-07 00:31:45

Why not try adding the Id's column name to Id field of Vehicle, like so: @Id @Column(name="ID") public int getId() { return this.id; }

Cuga 2009-05-07 01:23:37

Answer 6

A:

I just ran into this. Has anyone found an answer? It looks like it might be a hibernate bug

[http://opensource.atlassian.com/projects/hibernate/browse/HHH-4250][1]

2010-03-23 17:32:44

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Splitting Hibernate Entity among 2 Tables

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