many-to-one problem

Logical · **Joined:** Fri Nov 21, 2003 10:58 am **Posts:** 4

Every Answer has a Question
Question knows all the Answers he has

If I retreive an Answer out of a HQL I can get the String attributes, but I can't get the Question object
answer.getStringAnswer() gives me the answer
answer.getQuestion() gives me NULL

Answer.java has the attributes
private Question question;
private int intAnswer;
private String stringAnswer;
private boolean booleanAnswer;

Question.java has the attributes
private List answers;
private String description;
private String answerType;
private boolean required;

Question.hbm.xml:

Code:

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE hibernate-mapping SYSTEM "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
<hibernate-mapping>
   <class name="com.xxess.platform.domain.Question" table="question">
      
      <id name="id">
         <generator class="native" />
      </id>
      
      <property name="description" type="java.lang.String"/>
      <property name="answerType" type="java.lang.String" />
      <property name="required" type="java.lang.Boolean" />

         <bag name="answers" lazy="true" inverse="true" cascade="all">
            <key column="question"/>
            <one-to-many class="com.xxess.platform.domain.Answer" />
        </bag>
        
   </class>
</hibernate-mapping>

Answer.hbm.xml:

Code:

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE hibernate-mapping SYSTEM "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
<hibernate-mapping>
   <class name="com.xxess.platform.domain.Answer" table="Answer">
      
      <id name="id">
         <generator class="native" />
      </id>
      
      <property name="intAnswer" type="java.lang.Integer"/>
      <property name="stringAnswer" type="java.lang.String" />
      <property name="booleanAnswer" type="java.lang.Boolean" />

        <many-to-one name="question" not-null="false" />

   </class>
</hibernate-mapping>

I tried about everything, but nothing worked :{
What am I doing wrong here ?

gavin · **Posted:** Fri Nov 21, 2003 11:19 am

broken get/set pair?

Logical · **Joined:** Fri Nov 21, 2003 10:58 am **Posts:** 4

what do you mean with broken ?

in the database I can see that the Answer actually has a Question
and every attribute has a public getter and setter in the code

by the way, the query to fetch the Answer is:

Quote:

select distinct new Answer(answer.id, answer.intAnswer, answer.stringAnswer, answer.booleanAnswer)
from Answer answer
where ....

gavin · **Posted:** Fri Nov 21, 2003 11:36 am

Well no wonder!!

What on earth is wrong with

Code:

from Answer where...

Logical · **Joined:** Fri Nov 21, 2003 10:58 am **Posts:** 4

the retreivel of the Answer is done correctly

Code:

select distinct new Answer(answer.id, answer.intAnswer, answer.stringAnswer, answer.booleanAnswer) 
from Answer answer 
where anser.id = '1234'

gives me an asnwer...

Code:

if(iterator.hasNext())
   answer = (Answer)iterator.next();
System.out.println(answer.getStringAnswer());

shows the String the answer contains (wich is correct)
while answer.getQuestion() retruns NULL

gavin · **Posted:** Fri Nov 21, 2003 12:30 pm

Does it seem reasonable to you that stringAnswer is properly initilized because it appears in the select clause, whereas question is not, because it does not?

Logical · **Joined:** Fri Nov 21, 2003 10:58 am **Posts:** 4

Stupid me !

the sollution indeed was:

Code:

select distinct new Answer(answer.id, answer.intAnswer, answer.stringAnswer, answer.booleanAnswer, question)
from Answer answer, Question question
where answer.id = '1234'

max · **Posted:** Sat Nov 22, 2003 8:23 am

eh ? Why are you using the new Answer(x,y,z) construct instead of just doing "from Answer where id = 42" ?

Do you want the complete object or just a partial content ?

If complete: then use "from Answer ..."
If partial: then use the "select new Answer(...) from Answer"