error while mapping to child table directly

[JayaSiji Gopal]

I have the following scenario:

Article table, which has all article related information.
A article can have one or more attachments, stored in article_attachments table.
Article_attachments has composite key for which we have articleAttachmentsId bean.

Following is the mapping in hbm.xml file:

<class name="com.mhc.sandp.msa.app.beans.article.Article"
          table="(SELECT A.*,(SELECT B.CATEGORY_NAME FROM MSA_CATEGORY B WHERE A.ARTICLE_CODE=B.CATEGORY_CODE)ARTICLE_CODE_DESC
               FROM ARTICLE A)" >
      <id name="articleId" column="ARTICLE_ID"></id>
<property....../>
<set name="articleAttachments" batch-size="200" lazy="true">
         <key column="ARTICLE_ID" />
         <one-to-many class="com.mhc.sandp.msa.app.beans.article.ArticleAttachments"  />
</set>   
<class name="com.mhc.sandp.msa.app.beans.article.ArticleAttachments" table="ARTICLE_ATTACHMENTS">
        <composite-id name="id" class="com.mhc.sandp.msa.app.beans.article.ArticleAttachmentsId">
            <key-property name="articleId" column="ARTICLE_ID" />
            <key-property name="attachmentName" column="ATTACHMENT_NAME" />
        </composite-id>   
      <property name="attachment" column="ATTACHMENT" />
    </class>

articleattachments and articleattachmentsid bean are as follows:

public class ArticleAttachmentsId implements Serializable {
private Long articleId;
   private String attachmentName;
   
   public ArticleAttachmentsId(){}
   
   public ArticleAttachmentsId(Long articleId, String attachmentName){
      this.articleId=articleId;
      this.attachmentName=attachmentName;
   }

   public Long getArticleId() {
      return articleId;
   }

   public void setArticleId(Long articleId) {
      this.articleId = articleId;
   }

   public String getAttachmentName() {
      return attachmentName;
   }

   public void setAttachmentName(String attachmentName) {
      this.attachmentName = attachmentName;
   }
   
   public String toString(){
       StringBuffer sb = new StringBuffer();
       sb.append(" articleId="+articleId);
       sb.append(" attachmentName="+attachmentName);
       return sb.toString();
    }      
}

public class ArticleAttachments implements Serializable{

   private static final long serialVersionUID = -1893810557780172873L;
   private ArticleAttachmentsId id;
   private byte[] attachment;
   
   public ArticleAttachments(){}
   
   public ArticleAttachments(ArticleAttachmentsId id,byte[] attachment){
      this.id=id;
      this.attachment=attachment;
   }
   
   public ArticleAttachmentsId getId() {
      return id;
   }
   public void setId(ArticleAttachmentsId id) {
      this.id = id;
   }
   public byte[] getAttachment() {
      return attachment;
   }
   public void setAttachment(byte[] attachment) {
      this.attachment = attachment;
   }
   
   public String toString(){
       StringBuffer sb = new StringBuffer();
       sb.append(" MsaArticleAttachId="+id);
       sb.append(" attachment="+attachment);
       return sb.toString();
    }      
   
}

I know the articleId and attachmentname and would like to retrieve the ATTACHMENT from the table. I wrote the following code:

List<ArticleAttachments> content = new ArrayList<ArticleAttachments>();

            DetachedCriteria detachedcriteria = DetachedCriteria.forClass(ArticleAttachments.class);

            detachedcriteria.createAlias("id", "id");

            detachedcriteria.add(Restrictions.eq("id.articleId", articleId));

            detachedcriteria.add(Restrictions.eq("id.attachmentName", attachmentName));

            content.addAll(getHibernateTemplate().findByCriteria(detachedcriteria));

            return content.get(0);

I get the following exception:

Caused by: org.hibernate.QueryException: could not resolve property: articleId of: com.mhc.sandp.msa.app.beans.article.ArticleAttachments

      at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:44)

      at org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:38)

      at org.hibernate.persister.entity.AbstractEntityPersister.getSubclassPropertyTableNumber(AbstractEntityPersister.java:1379)

      at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:31)

      at org.hibernate.persister.entity.AbstractEntityPersister.toColumns(AbstractEntityPersister.java:1354)

      at org.hibernate.loader.criteria.CriteriaQueryTranslator.getColumns(CriteriaQueryTranslator.java:434)

      at org.hibernate.loader.criteria.CriteriaQueryTranslator.getColumnsUsingProjection(CriteriaQueryTranslator.java:394)

      at org.hibernate.criterion.SimpleExpression.toSqlString(SimpleExpression.java:45)

      at org.hibernate.loader.criteria.CriteriaQueryTranslator.getWhereCondition(CriteriaQueryTranslator.java:334)

      at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:90)

      at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:59)

      at org.hibernate.loader.criteria.CriteriaLoader.<init>(CriteriaLoader.java:67)

      at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1550)

      at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)

Dont understand y it is searching for articleId in articleAttachments table, when i have created an alias? also trying to see if there is a resolution to this problem.
Please help. Any ideas.

Thank you!
Jayashree.

[Mark Spritzler]

did you need the alias(). Looking at your query I don't see why you need the alias at all.

What happens if you remove the createAlias() call?

Mark

[JayaSiji Gopal]

The articleId is present in ArticleAttachmentsId bean, a composite key in article_attachments table.
If I were to remove the alias, how would I let the bean know to look for articleId and attachment name in articleattachmentsid bean.

The attachment itself , a byte[] is in articleattachments bean.

I also tried this approach:

  
List<ArticleAttachments> content = new ArrayList<ArticleAttachments>();
		ArticleAttachments attachment = null;
		DetachedCriteria detachedcriteria = DetachedCriteria.forClass(ArticleAttachments.class);
		detachedcriteria.createAlias("id", "id");
		detachedcriteria.add(Restrictions.eq("id.articleId", articleId));
		detachedcriteria.add(Restrictions.eq("id.attachmentName", attachmentName));
		content.addAll(getHibernateTemplate().findByCriteria(detachedcriteria));
		return content.get(0);

Here again i get the same exception as above.

[Mark Spritzler]

JayaSiji Gopal wrote:The articleId is present in ArticleAttachmentsId bean, a composite key in article_attachments table.
If I were to remove the alias, how would I let the bean know to look for articleId and attachment name in articleattachmentsid bean.

The attachment itself , a byte[] is in articleattachments bean.

I also tried this approach:

  
List<ArticleAttachments> content = new ArrayList<ArticleAttachments>();
		ArticleAttachments attachment = null;
		DetachedCriteria detachedcriteria = DetachedCriteria.forClass(ArticleAttachments.class);
		detachedcriteria.createAlias("id", "id");
		detachedcriteria.add(Restrictions.eq("id.articleId", articleId));
		detachedcriteria.add(Restrictions.eq("id.attachmentName", attachmentName));
		content.addAll(getHibernateTemplate().findByCriteria(detachedcriteria));
		return content.get(0);

Here again i get the same exception as above.

because you have it mapped directly in the ArticleAttaments class as a composite id, so the id property is already there.

Have you removed it, detachedcriteria.createAlias("id", "id");
from your code and tried it yet?

Mark

[JayaSiji Gopal]

Ok..i do understand what you are saying...but if you remove the alias, how would i supply articleId & attachmentName as restrictions to the detached criteria.

I tried :

    

# List<ArticleAttachments> content = new ArrayList<ArticleAttachments>();  
#         ArticleAttachments attachment = null;  
#         DetachedCriteria detachedcriteria = DetachedCriteria.forClass(ArticleAttachments.class);  
#         detachedcriteria.add(Restrictions.eq("articleId", articleId));  
#         detachedcriteria.add(Restrictions.eq("attachmentName", attachmentName));  
#         content.addAll(getHibernateTemplate().findByCriteria(detachedcriteria));  
#         return content.get(0); 

It still tries to look for articleId in articleAttachments, whereas it is actually present in ArticleAttachmentsId.