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composite key and single key mapping association

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hib_user

Post subject: composite key and single key mapping association

Posted: Tue Jun 19, 2007 11:03 am

Newbie

Joined: Mon Jun 11, 2007 2:58 pm
Posts: 11

Hi,

If i have table say, "TABLEA" which has a primary key on one column, lets say on "COLM1" and has another table "TABLEB", which has a composite key of two columns (COLM1 and COLM2).

If i want to have an association with these tables, what should i put in the mapping xml file?

CLASSA represents TABLEA
CLASSB represents TABLEB.

CLASSA has a reference to CLASSB.
COMPOSITECLASS for composite key of TABLEB.

is the following mapping file is correct or does it needs any changes. Can any body help me with this issue.

Code:

<class name="CLASSA" table="TABLEA">
      <id name="keyID" column="COLM1">
           <generator class="assigned" /> 
        </id>
      ..... some other properties.
      <property />
                <property />
      .........
      <one-to-one name="classB" class="CLASSB"/>

   </class>


<class name="CLASSB" table="TABLEB">
   
      <composite-id name="compKey" class="COMPOSITECLASS">
         <key-property name="colm2" column="COLM2" type="integer"/>
         <key-many-to-one name="keyID" class="CLASSA" column="COLM1"/>
      </composite-id>      

                ..... some other properties.
      <property />
                <property />
               
   </class>

with this configuration i am getting mapping exception...

org.hibernate.MappingException: broken column mapping for: classB.id of: CLASSA

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jits_1998

Post subject:

Posted: Tue Jun 19, 2007 11:37 am

Senior

Joined: Tue Jun 12, 2007 4:49 pm
Posts: 127
Location: India

ClassB must have a many-to-one mapping to classA, with unique="true".

Thats the hibernate's way of completing one-to-one.

regards,
Jitendra

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hib_user

Post subject:

Posted: Tue Jun 19, 2007 11:49 am

Newbie

Joined: Mon Jun 11, 2007 2:58 pm
Posts: 11

but there is no "unique" attribute defined for <key-many-to-one...> mapping tag ind dtd file. I tried, it and it gives me exception, that "unique" attribute is not defined.

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jits_1998

Post subject: Re:

Posted: Tue Jun 19, 2007 5:29 pm

Senior

Joined: Tue Jun 12, 2007 4:49 pm
Posts: 127
Location: India

Sorry i missed the one-to-one part. Try this:

Code:

<class name="ClassA" lazy="true" >

      <id name="id" column="id" type="long" unsaved-value="0">
          <generator class="increment"/>
      </id>
      
      <many-to-one name="classB" class="ClassB" unique="true">
         <column name="b_id" />
         <column name="a_id" />
      </many-to-one>
      
      <property name="note"/>


   </class>

   <class name="ClassB" >
      <composite-id class="ClassC" name="classC" >
         <key-property name="id" type="long"  ></key-property>
         <key-many-to-one name="classA" column="a_id" ></key-many-to-one>
      </composite-id>
      
      <property name="name"></property>
      
   </class>

*Please do rate if this helps*

Regards,
Jitendra

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