many-to-one with at least one parent

mzoom · **Joined:** Tue Feb 03, 2004 1:49 pm **Posts:** 16

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
    
<hibernate-mapping schema="test">
   <class name="com.Parent" table="parents">
      <id name="id" type="java.lang.Long" unsaved-value="null">
         <generator class="native"/>
      </id>
      <version name="version" type="java.lang.Long" unsaved-value="null"/>
      <bag name="children" inverse="true" lazy="true" cascade="all-delete-orphan">
         <key>
            <column name="parent_fk"/>
         </key>
         <one-to-many class="com.Child"/>
      </bag>
      <property name="name" type="java.lang.String"/>
   </class>
   <class name="com.Child" table="childs">
      <id name="id" type="java.lang.Long" unsaved-value="null">
         <generator class="native"/>
      </id>
      <version name="version" type="java.lang.Long" unsaved-value="null"/>
      <many-to-one name="parent" not-null="true" cascade="save-update" class="com.Parent">
         <column name="parent_fk"/>
      </many-to-one>
      <property name="name" type="java.lang.String"/>
   </class>   
</hibernate-mapping>

-- my code --

txn = session.beginTransaction();
Child child = new Child();
child.setName("this child should not in db");
//
session.save(child);
session.flush();
txn.commit();

The problem is the child without parent can still be inserted into database. How to do in the mapping file so that -- a child without parent will be rejected?

emmanuel · **Posted:** Mon Feb 09, 2004 6:07 am

not-null="true"

mzoom · **Joined:** Tue Feb 03, 2004 1:49 pm **Posts:** 16

emmanuel wrote:

not-null="true"

Where else should I put the not-null="true"?

(I already have one in the mapping file.)

mzoom · **Joined:** Tue Feb 03, 2004 1:49 pm **Posts:** 16

tested here --

Code:

      <many-to-one name="parent" cascade="save-update" class="com.Parent"> 
         <column name="parent_fk"/> 
      </many-to-one> 

It works.

But, not for this composite-id mapping

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
    
<hibernate-mapping schema="test">
   <class name="com.Composite" table="composites">
      <composite-id name="comp_id" class="com.CompositePK"> 
         <key-property name="id" column="id" type="java.lang.Long"/>
         <key-property name="name" column="name"   type="java.lang.String"/>
      </composite-id>
      <version name="version" type="java.lang.Long" unsaved-value="null"/>
      <bag name="children" inverse="true" lazy="true" cascade="all-delete-orphan">
         <key>
            <column name="id_fk"/>
            <column name="name_fk"/>
         </key>
         <one-to-many class="com.Composite"/>
      </bag>
      <many-to-one name="parent" cascade="save-update" class="com.Composite">
         <column name="id_fk" not-null="true"/>
         <column name="name_fk" not-null="true"/>
      </many-to-one>
      <property name="description" type="java.lang.String"/>
   </class>
</hibernate-mapping>

result-errors

Code:

[junit] Testcase: testAddComposite(com.CompositeTest):      Caused an ERROR
[junit] not-null property references a null or transient value: com.Composite.parent
[junit] net.sf.hibernate.PropertyValueException: not-null property references a null or transient value: com.Composite.parent
[junit]     at net.sf.hibernate.impl.SessionImpl.checkNullability(SessionImpl.java:1248)
[junit]     at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:902)
[junit]     at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:839)
[junit]     at net.sf.hibernate.impl.SessionImpl.saveWithGeneratedIdentifier(SessionImpl.java:761)
[junit]     at net.sf.hibernate.impl.SessionImpl.save(SessionImpl.java:720)
[junit]     at com.CompositeTest.testAddComposite(CompositeTest.java:39)

emmanuel · **Posted:** Mon Feb 09, 2004 8:35 am

To summarize

Code:

<many-to-one name="parent" cascade="save-update" class="com.Composite">
         <column name="id_fk" not-null="true"/>
         <column name="name_fk" not-null="true"/>
      </many-to-one>

don"t raise 'not-null property references a null or transient value'

but

Code:

<many-to-one name="parent" not-null="true" cascade="save-update" class="com.Parent">
         <column name="parent_fk"/>
      </many-to-one>

Does.

Is that correct ?

mzoom · **Joined:** Tue Feb 03, 2004 1:49 pm **Posts:** 16

Sorry.

Quote:

<many-to-one name="parent" cascade="save-update" class="com.Composite">
<column name="id_fk" not-null="true"/>
<column name="name_fk" not-null="true"/>
</many-to-one>

The above mapping cause errors. raise 'not-null property references a null or transient value' when it tried to add data into database. I guess, it is due to only one table being used. Haven't tested on two tables with composite-id.

and,

Quote:

<many-to-one name="parent" not-null="true" cascade="save-update" class="com.Parent">
<column name="parent_fk"/>
</many-to-one>

The above code -- don"t raise 'not-null property references a null or transient value', but a child without parent will still get inserted into database.

and,

Code:

<many-to-one name="parent" cascade="save-update" class="com.Parent">
         <column name="parent_fk" not-null="true"/>
      </many-to-one>

The above code works, and a child without parent will NOT get inserted into database.

emmanuel · **Posted:** Mon Feb 09, 2004 9:20 am

The last one should have raised an exception.

mzoom · **Joined:** Tue Feb 03, 2004 1:49 pm **Posts:** 16

u r right.

emmanuel · **Posted:** Mon Feb 09, 2004 9:28 am

So 1st and 3rd do the same thing as expected.

the second cannot work 'cause you're mixing <column> usage with <many-to-one column> usage (using some attribute as if you where using the second syntax).