Hibernate Join Problems

[Robert Wiscup]

Hi All,

I'm trying to do this SQL join in HQL in Hibernate . . .

   SELECT FA.AreaName as FunctionalArea from Defect D JOIN functionalArea FA on FA.functionalAreaId = D.functionalAreaId

basically a join on Defect and FunctionalArea Table. However, I'm still learning Hibernate and I don't understand how to do the configuration properly and the exact HQL syntax. Here's what I have now:

************ Defect.hbm.xml ********************

    
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="gov.ohio.odjfs.struts">

<class name="Defect" table="Defect">
	<id name="defectId" type="integer" column="DEFECTID">
		<generator class="native"/>
	</id>
	<property name="description" type="string"/>  
	<property name="priorityId" type="integer"/>
	<property name="reportDateTime" type="date" column="REPORTDATETIME" />
	
	<property name="reporterUserId" type="integer"/>
	<property name="functionalAreaId" type="integer"/>
	<property name="statusId" type="integer"/>
	<property name="severity" type="string"/> 
	<property name="teamLeadId" type="integer"/>
	<property name="detectionDateTime" type="date"/>
	<property name="estFixTime" type="integer"/>
	<property name="actFixTime" type="integer"/>
	<property name="statusDate" type="date"/>
	<property name="assignedToUserId" type="integer"/>
	<property name="assignedToDate" type="date"/>
	<property name="fixedByUserId" type="integer"/> 

	<set name="functionalareas" table="FUNCTIONALAREA" cascade="persist,delete">
                   <key column="FUNCTIONALAREAID" />
                   <one-to-many class="FunctionalArea"/>
                </set>
</class> 
</hibernate-mapping>            

************ FunctionalArea.hbm.xml ********************

    
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="gov.ohio.odjfs.struts">

<class name="FunctionalArea" table="FunctionalArea">
	<id name="functionalAreaId" type="integer" column="FUNCTIONALAREAID">
		<generator class="native"/>
	</id>
	
	<property name="areaName" type="string"/> 
</class> 

</hibernate-mapping>      

Can anyone tell me if I've done the associations and join syntax correctly?

Thanks,

Rob

[Mark Spritzler]

Well mapping is only half the part. You mapped your association. Now in HQL you have to say you want to fetch the association. So the FROM portion of your HQL would look like.

"From Defect d JOIN d.functionalareas"

Now make sure you follow Java standard on property names and using correct capitalization and camel casing. I would expect to see Defect has a property called functionalAreas, when the A, since it starts a new word is capitalized. And in the HQL the alias be a lower case d, not "D"

Hope that helps

Mark

[Prashant R Kataria]

I doubt your mapping will not work.

  
<set name="functionalareas" table="FUNCTIONALAREA" cascade="persist,delete">  
            <key column="FUNCTIONALAREAID" />  
            <one-to-many class="FunctionalArea"/>  
</set>  

<id name="functionalAreaId" type="integer" column="FUNCTIONALAREAID">  
       <generator class="native"/>  
</id> 

Key column will map to a foreign key in funcionalarea table, I can see that both pk and fk of functional area share the same name with pk having id generator as native in functionalarea. This is wrong.

You should use different name for foreign key and then follow Mark.

[Robert Wiscup]

Hi Mark, Prashant,

Thanks for your help . . .

Ok, now the two queries below seem to execute without error but I get no results . . .

    
   //sb.append("select fa.areaName From Defect d JOIN d.functionalAreas as fa");
   sb.append("select st.userName From Defect d JOIN d.staff as st");
		       
   results = session.createQuery(sb.toString()).list();

so I'm missing something else apparently . . . working on this . . .



Oh, and here's a little more information:

In the end, I'm actually trying to execute the HQL equivalent of the following sql:

    
SELECT D.DEFECTID, D.DESCRIPTION, P.DESCRIPTION as Priority, D.REPORTDATETIME as ReportDate, SF.USERNAME as Reporter, FA.AreaName as FunctionalArea, 
S.Description as Status, D.SEVERITY as Severity FROM Priority P 
JOIN Defect D on P.priorityId = D.priorityId
JOIN Status S on S.statusId = D.statusId 
JOIN functionalArea FA on FA.functionalAreaId = D.functionalAreaId
JOIN Staff SF on SF.staffId = D.reporterUserId  

I would like the list that results from the HQL equivalent of the above SQL to be of type "DEFECT" so I can use the displaytag library to display it (here, I admit I'm assuming that it has to be a list of type DEFECT and not just an array of generic objects) . . . At any rate, that's where I want to get to eventually . . .

Rob

[Robert Wiscup]

Robert Wiscup wrote:Hi All,

I'm trying to do this SQL join in HQL in Hibernate . . .

   SELECT FA.AreaName as FunctionalArea from Defect D JOIN functionalArea FA on FA.functionalAreaId = D.functionalAreaId

basically a join on Defect and FunctionalArea Table. However, I'm still learning Hibernate and I don't understand how to do the configuration properly and the exact HQL syntax. Here's what I have now:

************ Defect.hbm.xml ********************

    
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<class name="Defect" table="Defect">
	<id name="defectId" type="integer" column="DEFECTID">
		<generator class="native"/>
	</id>
	<property name="description" type="string"/>  
	<property name="priorityId" type="integer"/>
	<property name="reportDateTime" type="date" column="REPORTDATETIME" />
	
	<property name="reporterUserId" type="integer"/>
	<property name="functionalAreaId" type="integer"/>
	<property name="statusId" type="integer"/>
	<property name="severity" type="string"/> 
	<property name="teamLeadId" type="integer"/>
	<property name="detectionDateTime" type="date"/>
	<property name="estFixTime" type="integer"/>
	<property name="actFixTime" type="integer"/>
	<property name="statusDate" type="date"/>
	<property name="assignedToUserId" type="integer"/>
	<property name="assignedToDate" type="date"/>
	<property name="fixedByUserId" type="integer"/> 

	<set name="functionalareas" table="FUNCTIONALAREA" cascade="persist,delete">
                   <key column="FUNCTIONALAREAID" />
                   <one-to-many class="FunctionalArea"/>
                </set>
</class> 
</hibernate-mapping>            

************ FunctionalArea.hbm.xml ********************

    
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<class name="FunctionalArea" table="FunctionalArea">
	<id name="functionalAreaId" type="integer" column="FUNCTIONALAREAID">
		<generator class="native"/>
	</id>
	
	<property name="areaName" type="string"/> 
</class> 

</hibernate-mapping>      

Can anyone tell me if I've done the associations and join syntax correctly?

Thanks,

Rob