I am attempting to create a one-to-many relationship between 2 data objects using hibernate and xdoclet. I have been through much of the documentation, but still need some help.

I have 2 classes: Album and Image, both listed below (in part). The superclass contains the generated id. :

[quote]
/**
* @hibernate.class
* table="image"
* @hibernate.subclass
* discrimator-value="image"
*/
public class Image extends BaseDataObject
{

public Image(){}


/**
* @hibernate.many-to-one
* not_null="true"
*
*/
public Album getAlbum()
{
return album;
}

/**
* @hibernate.property
* column="description"
*
*
*/
public String getDescription()
{
return description;
}

/**
* @hibernate.property
* column="filename"
*
*
*/
public String getFilename()
{
return filename;
}

/**
* @hibernate.property
* column="owner"
*
*
*/
public String getOwner()
{
return owner;
}

/**
* @hibernate.property
* column="thumbnailFilename"
*
*
*/
public String getThumbnailFilename()
{
return thumbnailFilename;
}

/**
* @hibernate.property
* column="title"
*
*
*/
public String getTitle()
{
return title;
}


}
[/quote]

[quote]

import java.util.*;

/**
* @hibernate.class
* table="album"
* @hibernate.subclass
* discrimator-value="album"
*/
public class Album extends BaseDataObject
{

public Album(){}


/**
* @hibernate.property
* column="date"
*
*
*/
public String getDate()
{
return date;
}

/**
* @hibernate.property
* column="description"
*
*
*/
public String getDescription()
{
return description;
}

/**
* @hibernate.property
* column="owner"
*
*
*/
public String getOwner()
{
return owner;
}

/**
* @hibernate.property
* column="title"
*
*
*/
public String getTitle()
{
return title;
}


/**
* @hibernate.set
* lazy="true"
* cascade="all"
* inverse="true"
*
* @hibernate.collection-one-to-many
* class="com.sullins.data.Image"
*
* @hibernate.collection-key
* column="album_id"
*/
public Set getImages()
{
return images;
}

}

[/quote]

The following is the code I am using to save an Album instance:

[quote]

logger.debug( obj.toString() );
Transaction trans = hibernateSession.beginTransaction();
hibernateSession.save(obj);

Set images = obj.getImages();

hibernateSession.save( images );

logger.debug( "album has been saved" );
trans.commit();
[/quote]



and finally, the log file portion generated:

[quote]

####<saving [com.sullins.data.Album#<null>]>
####<processing cascades for: com.sullins.data.Album>
####<done processing cascades for: com.sullins.data.Album>
####<Wrapped collection in role: com.sullins.data.Album.images>
####<Inserting entity: com.sullins.data.Album (native id)>
####<about to open: 0 open PreparedStatements, 0 open ResultSets>
####<prepared statement get: insert into album (date, description, owner, title) values (?, ?, ?, ?)
>
Hibernate: insert into album (date, description, owner, title) values (?, ?, ?, ?)
####<preparing statement>
####<Dehydrating entity: com.sullins.data.Album#null>
####<binding '21-0-2004' to parameter: 1>
####<binding 'I wonder how I should make paragraphs?' to parameter: 2>
####<binding 'bsullins' to parameter: 3>
####<binding 'The new title for it' to parameter: 4>
####<done closing: 0 open PreparedStatements, 0 open ResultSets>
####<closing statement>
####<about to open: 0 open PreparedStatements, 0 open ResultSets>
####<prepared statement get: SELECT LAST_INSERT_ID()>
Hibernate: SELECT LAST_INSERT_ID()
####<preparing statement>
####<Natively generated identity: 0>
####<done closing: 0 open PreparedStatements, 0 open ResultSets>
####<closing statement>
####<processing cascades for: com.sullins.data.Album>
####<cascading to collection: com.sullins.data.Album.images>
####<cascading to saveOrUpdate()>
####<unsaved-value strategy NULL>
####<saveOrUpdate() previously saved instance with id: 0>
####<updating [com.sullins.data.Image#0]>
####<done processing cascades for: com.sullins.data.Album>

[/quote]

As a result, only the Album instance is saved, no Image instances. There is 1 image attached to the Album in this scenario.

Reread the Parent/Child relationship chapter of the reference guide and http://www.hibernate.org/Documentation/InsideExplanationOfInverseTrue

[quote="emmanuel"]Reread the Parent/Child relationship chapter of the reference guide and [url]http://www.hibernate.org/Documentation/InsideExplanationOfInverseTrue[/url][/quote]

I did, and I thought I had it right. Are you saying I should change the inverse="true" to false? I will reread to be sure of my assumptions.

Also, do I need to explicitly save both the album and the Set of images, or is there a way to just save the album and have it also save the contained images?

Thanks for your reply.

Yep, you don't have the other side, so false is required to save the association


The concept of saving the set is irrevelent. only object are saved in Hibernate.
Using cascade="all", a save of album will save every associated image. If you had used cascade="none", you'd have to save every image individually.

Not sure what you mean by not having the other side. Image has a getAlbum method.


[quote="emmanuel"]Using cascade="all", a save of album will save every associated image. If you had used cascade="none", you'd have to save every image individually.[/quote]

I went ahead and set inverse to false, changed to cascade all, but still no luck. The log is the same. I think I am missing something....

I appreciate your help, thanks.

You mapped getAlbum => inverse="true" is good, sorry

Show the mapping and exact code (including obj build), don't do save(images) it's pointless.

The album instance is saved everytime, but no image instances. Here is the storage code:



The source of the persistent object remains as in the first post. Here are the generated mapping files:





and here is the log output:



Thanks again, I know this is probably something trivial, but I do appreciate the help.

Why do you say image is not inserted,
it seems to be alreadfy in DB with id 0, so updated, not inserted.

That is what is so confusing to me. There is actually nothing in that table before the save, and nothing after. The album table gets 1 row inserted, the image table has nothing. I clear out both tables between tests to be sure.

Show the simpliest version of your code, mapping, ...

Sorry, I don't know what you want...

Sorry, I read too fast.
Try to do the following:
set show_sql to true in your hibernate config file
clear all data in your DB
try to add a simple image using saveOrUpdate, and check the success.
try to save an album having images and check sucess.
Your mapping seems fine.

Ok, I switched to a saveOrUpdate() call, and it appears to have gotten a little further. However, this time, neither the album or the image got saved. Here is the code for the save:



and the log:



should I be doing a flush() before the commit?

Hibernate guess the objects need to be updated, not saved.
I think you use a primitive type as id => set unsaved-value="0"
or have a broken setter/getter of id.
Check unsaved-value in the reference guide

I have my getId() and setId() in a baseclass, would that effect it?