Inheritance problem: Error while persisting object

imsathya · **Joined:** Mon Nov 08, 2004 4:05 am **Posts:** 6

Hibernate version: 3.1

Friends,
I am sorry if this is a very trivial and oft-repeated problem. I did look around a little and could not find anything very helpful. Pl help.

I am running into a problem when trying to save an entity extending from an abstract base class which simply holds the primary ID (common to all entities). Here is my code :

Parent Class

Code:

public abstract class BaseEntity<T extends java.io.Serializable> {
   private T id;
   
   public T getId() {return this.id;}
   public void setId(T id) {this.id = id;}
}

Child Class

Code:

public class Address<Integer> extends BaseEntity {
   String addressText, city;

    public String getAddressText() {
      return addressText;
   }
   public void setAddressText(String addressText) {
      this.addressText = addressText;
   }
   public String getCity() {
      return city;
   }
   public void setCity(String city) {
      this.city = city;
   }
}

There may be other implementations of the BaseEntity as well.

The mapping file for Address (using the table-per-concrete-class strategy) :

Code:

<hibernate-mapping package="com.vca.paws.datamodel" >
  <class name="Address" table="Address" polymorphism="implicit">
   <id name="id" type="integer" unsaved-value="null" >
      <column name="id" not-null="true"/>
       <generator class="increment"/>
      </id>
      
           <property column="addressText" name="addressText" type="string" not-null="true"/>
      <property column="city" name="city" type="string" not-null="true"/>
</hibernate-mapping>

Now, when I try to save or update an Address entity, I get the below error :

Code:

Could not execute JDBC batch update; bad SQL grammar [update Address set addressText=?, city=? where id=?]; nested exception is java.sql.BatchUpdateException: No value specified for parameter

Could you pl point me where I am going wrong ?

Anyinputs would be most welcome !

Thanks.[/code]

LaLiLuna · **Posted:** Wed Apr 05, 2006 5:37 pm

Hibernate tries to update instead of saving your new entry. So it assumes that the id is specified.

You may try to remove the
unsaved-value="null" from your id mapping.

Regards Sebastian

imsathya · **Joined:** Mon Nov 08, 2004 4:05 am **Posts:** 6

I am sorry for having troubled you all on this.. this was a problem with the way I had used the generic type in my child class. It should have been :

Code:

public class ChildClass extends Parent<Integer> {..}

It works like a charm now !

Thanks , and sorry again for the bad post.