I have a many to many relationship solved with a join table.

My business requirements are such that there exists a many to many relationship between user and technology. This is resolved with the table user_technology.

So whenever I want to associate a user to a technology what I essentially need to do is an insert into the user_technology table. My code for that follows (with spring framework):

public void saveTechnologyForUser(final UserVO user, final TechnologyVO tech) {

HibernateTemplate template = getHibernateTemplate();
template.execute(
new HibernateCallback(){

public Object doInHibernate(Session session) throws HibernateException {

user.addTechnology(tech);
session.update(user);
log.info("Saved user with email " + user.getEmail());
return null;
}
}
);
}

What ends up happening is that hibernate does 4 queries. It updates the user table, it updates the technology table, it deletes from the join table (user_technology) based on the user_id and then it inserts into the user_technology table the user id and technology id. This seems like way too much work for what amounts to just an insert into the join table. Is there a way to do this so that you can get hibernate to just do an insert into the join table without the other queries. The other queries are un-necessary for my needs. On top of that, I need to keep the user's data in the join table and therefore I can't have hibernate delete it and then reinsert based on the user id. This is because a user may be associated to more than one technology

My mapping docs are below. The Technology object knows nothing about Users. I wanted Users to manage the relationship.

<?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>
<class
name="com.securance.vo.SecuranceUserVO"
table="auditapp_user"
dynamic-update="false"
dynamic-insert="false"
>

<id
name="userId"
column="user_id"
type="java.lang.Integer"
>
<generator class="native">
</generator>
</id>

<property
name="businessEntity"
type="java.lang.String"
update="true"
insert="true"
column="business_entity"
/>

<property
name="firstName"
type="java.lang.String"
update="true"
insert="true"
column="first_name"
/>

<property
name="lastName"
type="java.lang.String"
update="true"
insert="true"
column="last_name"
/>

<property
name="password"
type="java.lang.String"
update="true"
insert="true"
column="password"
/>

<property
name="phoneNumber"
type="java.lang.String"
update="true"
insert="true"
column="phone_number"
/>

<property
name="subscribed"
type="char"
update="true"
insert="true"
column="subscribed"
/>

<set
name="techs"
table="user_technology"
lazy="true"
inverse="false"
cascade="all"
sort="unsorted"
>

<key
column="user_id"
/>

<many-to-many
class="com.securance.vo.TechnologyVO"
column="tech_id"
outer-join="auto"
/>

</set>

<property
name="email"
type="java.lang.String"
update="true"
insert="true"
column="email"
/>

<!--
To add non XDoclet property mappings, create a file named
hibernate-properties-SecuranceUserVO.xml
containing the additional properties and place it in your merge dir.
-->

</class>

<query name="findByEmailAndPassword"><![CDATA[
from SecuranceUserVO user where user.email = :email and user.password = :password
]]></query>

</hibernate-mapping>

Any help with this is greatly appreciated.

Thanks

Post your JavaBeans code.

/*
* Created on Jul 6, 2004
*
* To change the template for this generated file go to
* Window&gt;Preferences&gt;Java&gt;Code Generation&gt;Code and Comments
*/
package com.securance.vo;

import java.util.HashSet;
import java.util.Set;

/**
* @author SC
*
* @hibernate.class
* table="auditapp_user"
*
* @hibernate.query
* name="findByEmailAndPassword"
* query="from SecuranceUserVO user where user.email = :email and user.password = :password"
*
*/
public class SecuranceUserVO extends BaseVO {

private Set techs = new HashSet();
private Integer userId;
private String businessEntity;
private String firstName;
private String lastName;
private String phoneNumber;
private String password;
private char subscribed;
private boolean authenticated;
private String email;


/**
* @hibernate.property
* column="business_entity"
*/
public String getBusinessEntity() {
return businessEntity;
}

/**
* @hibernate.property
* column="first_name"
*/
public String getFirstName() {
return firstName;
}

/**
* @hibernate.property
* column="last_name"
*/
public String getLastName() {
return lastName;
}

/**
* @hibernate.property
* column="password"
*/
public String getPassword() {
return password;
}

/**
* @hibernate.property
* column="phone_number"
*/
public String getPhoneNumber() {
return phoneNumber;
}

/**
* @hibernate.property
* column="subscribed"
*/
public char getSubscribed() {
return subscribed;
}

/**
* @hibernate.set
* table="user_technology"
* inverse="false"
* lazy="true"
* cascade="all"
* @hibernate.collection-key
* column="user_id"
* @hibernate.collection-many-to-many
* class="com.securance.vo.TechnologyVO"
* column="tech_id"
*
*/
public Set getTechs() {
return techs;
}

/**
* @hibernate.id
* generator-class="native"
* column="user_id"
*/
public Integer getUserId() {
return userId;
}

/**
* @param string
*/
public void setBusinessEntity(String string) {
businessEntity = string;
}

/**
* @param string
*/
public void setFirstName(String string) {
firstName = string;
}

/**
* @param string
*/
public void setLastName(String string) {
lastName = string;
}

/**
* @param string
*/
public void setPassword(String string) {
password = string;
}

/**
* @param string
*/
public void setPhoneNumber(String string) {
phoneNumber = string;
}

/**
* @param c
*/
public void setSubscribed(char c) {
subscribed = c;
}

/**
* @param set
*/
public void setTechs(Set set) {
techs = set;
}

/**
* @param integer
*/
public void setUserId(Integer integer) {
userId = integer;
}

/**
* @return
*/
public boolean isAuthenticated() {
return authenticated;
}

/**
* @param b
*/
public void setAuthenticated(boolean b) {
authenticated = b;
}

/**
* @hibernate.property
* column="email"
*/
public String getEmail() {
return email;
}

/**
* @param string
*/
public void setEmail(String string) {
email = string;
}

//utility method to add a Technology to a use
public void addTechnology(TechnologyVO tech){
if(tech == null){
throw new IllegalArgumentException("Null TechnologyVO");
}
tech.getUsers().add(this);
techs.add(tech);
}

}


package com.securance.vo;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

/**
* Created by IntelliJ IDEA.
* User: jalvarado
* Date: Jan 13, 2004
* Time: 2:17:43 AM
* To change this template use Options | File Templates.
*
* @hibernate.class table="technology"
*/
public class TechnologyVO implements Serializable {

private Integer technologyId;
private String technologyName;
private String description;
private ApTypeVO apType;
private Set steps = new HashSet();
private Set users = new HashSet();

/**
* @hibernate.id
* generator-class="native"
* column="tech_id"
*/
public Integer getTechnologyId() {
return technologyId;
}

public void setTechnologyId(Integer techId) {
this.technologyId = techId;
}
/**
* @hibernate.property
* column="technology"
*/
public String getTechnologyName() {
return technologyName;
}

public void setTechnologyName(String technologyName) {
this.technologyName = technologyName;
}
/**
* @hibernate.property
* column="description"
*/
public String getDescription() {
return description;
}

public void setDescription(String description) {
this.description = description;
}

/**
* @hibernate.many-to-one
* column="ap_type_id"
* outer-join="false"
*/
public ApTypeVO getApType() {
return apType;
}

public void setApType(ApTypeVO apType) {
this.apType = apType;
}

/**
* @hibernate.set
* table="ap_step_technology"
* inverse="true"
* lazy="true"
* @hibernate.collection-key
* column="tech_id"
* @hibernate.collection-many-to-many
* class="com.securance.vo.ApStepVO"
* column="ap_step_id"
*
*/
public Set getSteps() {
return steps;
}

/**
* @param set
*/
public void setSteps(Set set) {
steps = set;
}

/**
* @hibernate.set
* table="user_technology"
* inverse="true"
* lazy="true"
* @hibernate.collection-key
* column="tech_id"
* @hibernate.collection-many-to-many
* class="com.securance.vo.SecuranceUserVO"
* column="user_id"
*
*/
public Set getUsers() {
return users;
}

/**
* @param set
*/
public void setUsers(Set set) {
users = set;
}

}