From: <glassfish_at_javadesktop.org>
Date: Wed, 07 Mar 2007 04:52:31 PST

I have encountered a problem when removing a entity from the database. It seems that toplink does not remove the entries in the join table, when deleting entities with @OneToMany multiplicity. The derby database complains about toplink violating the join table constraints. Here is my test code:

EntityA.java:
-----------------
import javax.persistence.*;

@MappedSuperclass
public abstract class EntityA {
    private long id;

    @Id @GeneratedValue
    public long getId() {
        return id;
    }

    protected void setId(long id) {
        this.id = id;
    }
}

EntityB.java
-----------------
import javax.persistence.*;
import java.util.List;
import java.util.ArrayList;

@Entity
public class EntityB extends EntityA {
    private List<EntityC> foo = new ArrayList<EntityC>();

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    public List<EntityC> getFoo() {
        return foo;
    }

    public void setFoo(List<EntityC> foo) {
        this.foo = foo;
    }

    public void addFoo(EntityC foo) {
        getFoo().add(foo);
    }
}

EntityC.java:
------------------
import javax.persistence.Entity;

@Entity
public class EntityC extends EntityA {
    String s;

    protected EntityC() {
    }

    public EntityC(String s) {
        this.s = s;
    }

    public String getS() {
        return s;
    }

    public void setS(String s) {
        this.s = s;
    }
}

Test.java:
-------------
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

public class Test {
    public static void main(String[] args) {
        EntityManagerFactory emF = Persistence.createEntityManagerFactory("test");
        EntityManager em = emF.createEntityManager();
        EntityTransaction tx = em.getTransaction();
        EntityB obj;

        tx.begin();
        obj = new EntityB();
        obj.addFoo(new EntityC("First EntityC"));
        obj.addFoo(new EntityC("Second EntityC"));
        obj.addFoo(new EntityC("Third EntityC"));
        em.persist(obj);
        em.flush();
        em.remove(obj);
        tx.commit();
    }
}

My persistence.xml:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
          http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
             version="1.0">
    <persistence-unit name="test">
        <provider>oracle.toplink.essentials.PersistenceProvider</provider>
        <class>EntityA</class>
        <class>EntityB</class>
        <class>EntityC</class>
        <properties>
            <property name="toplink.jdbc.driver" value="org.apache.derby.jdbc.EmbeddedDriver"/>
            <property name="toplink.jdbc.url" value="jdbc:derby:Test;create=true"/>
            <property name="toplink.jdbc.user" value="APP"/>
            <property name="toplink.jdbc.password" value="APP"/>
            <property name="toplink.ddl-generation" value="create-tables"/>
        </properties>
    </persistence-unit>
</persistence>
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