one-to-two relation

steinkel · **Posted:** Wed Aug 04, 2004 5:13 am

Hi all:

This is a mapping-howto question

I have 2 classes:

-VersionedContent
-Content

There is a relation
VersionedContent --------------- Content
(one to two)

How can i best model it ?

THANKS.

Marcos Silva Pereira · **Posted:** Wed Aug 04, 2004 9:15 am

I think that you must to create two attributes Content in the VersionedContent class and so map each attributes like a one-to-one. This is simple and probably will work fine in your case. ;-)

valeuz...

steinkel · **Posted:** Thu Aug 05, 2004 4:52 am

Well, my solution is:

Code:

      <map name="relatedContents" cascade="all">
         <key column="keyRelContent"/>
         <!-- the index will be DRAFT or PUBLISHED -->
         <index column="publisherStatusIndexVersContent" type="java.lang.Integer"/>
         <one-to-many class="com.zz.contentManagement.model.Content"/>
      </map>

Then, into the VersionedContent Objet i have...

Code:

   public Content getPublishedContent() {
      if (this.getRelatedContents() == null
         || this.getRelatedContents().isEmpty()) {
         com.zzz.util.log.LogUtil.getDebugLogger().warn(
            "Inconsistent model, there is no map assigned for versioned content id = "
               + this.getId());
         return null;
      } else {
         return (Content) this.getRelatedContents().get(
            VersionedContent.RELATED_CONTENT_INDEX_PUBLISHED);
      }
   }

   public void setPublishedContent(Content content) {
      if (this.getRelatedContents() == null) {
         com.oneplanettravel.util.log.LogUtil.getDebugLogger().warn(
            "creating content map for VersionedContent = " + this.getId());
         this.setRelatedContents(new HashMap());
      }

      this.getRelatedContents().put(
         VersionedContent.RELATED_CONTENT_INDEX_PUBLISHED,
         content);

   }

   public Content getDraftContent() {
      if (this.getRelatedContents() == null
         || this.getRelatedContents().isEmpty()) {
         com.zzz.util.log.LogUtil.getDebugLogger().warn(
            "Inconsistent model, there is no map assigned for versioned content id = "
               + this.getId());
         return null;
      } else {
         return (Content) this.getRelatedContents().get(
            VersionedContent.RELATED_CONTENT_INDEX_DRAFT);
      }
   }

   public void setDraftContent(Content content) {
      if (this.getRelatedContents() == null) {
         com.zzz.util.log.LogUtil.getDebugLogger().warn(
            "creating content map for VersionedContent = " + this.getId());
         this.setRelatedContents(new HashMap());
      }

      this.getRelatedContents().put(
         VersionedContent.RELATED_CONTENT_INDEX_DRAFT,
         content);
   }

This is not so clean, but leaves the door open to a more complex version system (now there is only a 'one level' deep).

Thanks

lexi · **Joined:** Mon Aug 02, 2004 1:08 pm **Posts:** 42

I also don't understand why don't you just map two properties publishedContent and draftContent.

Marcos Silva Pereira · **Posted:** Thu Aug 05, 2004 10:43 am

IMHO you are adding unnecessary complexity to your model. If you really need only a one-2-two relationship, create two attributes and map each one them like a one-to-one seems more correct. At least for me.

valeuz...

steinkel · **Posted:** Thu Aug 05, 2004 1:30 pm

Ok, i'll do

I've used this approach because when i've used the "two one-to-one" approach, there were an error and i was saving the same object twice.

I didn't know how to solve this, so i did use the other dirty way.

Let's smite that demon...

steinkel · **Posted:** Tue Aug 10, 2004 9:58 am

Sorry, how can i do that mapping?

I used one-to-one, with this mapping

Code:

      <one-to-one name="draft" class="com.zzz.contentManagement.model.Content" cascade="all" />
      <one-to-one name="published" class="com.zzz.contentManagement.model.Content" cascade="all" />

But BOTH one-to-one mappings point to the SAME object (is this the expected behaviour?)

Sorry, i'm a newbe. Thanks.

steinkel · **Posted:** Fri Aug 13, 2004 9:49 am

SOLUTION

Anter reading a lot, finally the working mapping is...

Code:

      <many-to-one name="draft"
         class="com.zzz.contentManagement.model.Content"
         column="draft_idContent"
         cascade="all"
         unique="true"/>

      <many-to-one name="published"
         class="com.zzz.contentManagement.model.Content"
         column="published_idContent"
         cascade="all"
         unique="true"/>

Thanks!