I am having a problem with Hibernate not retrieving an inverse set.

I am using NetBeans 6.8 with the Hibernate Framework 3.2.5 and have used NetBeans to generate all of my config and POJO's from my mysql database model. I am using the InnoDB engine in mysql to enforce Foreign Key relationships.


I have three tables User, UserRoles and UserRole -

PK - Primary Key
FK - Foreign Key

User
-----
ID (PK)
Username
Password


UserRoles
-----------
ID (PK)
Username (FK -> User.Username)
Role (FK -> UserRole.Role)


UserRole
----------
Role
Description


I am issuing a Hibernate criteria query like this -

User u = (User)session.createCriteria(User.class).add(Restrictions.eq("username", username)).uniqueResult();

This returns the User and their details correctly. However when I call u.getUserRoleses(), then the Set returned is always empty. I was under the impression that Hibernate should lazy evaluate and give me the data set when I request it?

Is there some sort of problem with my mappings (below) or am I doing something wrong somehow?

My hibernate mappings files look like this -

User.hbm.xml
----------------
<hibernate-mapping>
<class catalog="accountablecare" name="uk.co.accountablecare.web.orm.generated.User" table="User">
<id name="id" type="java.lang.Integer">
<column name="ID"/>
<generator class="identity"/>
</id>
<property name="username" type="string">
<column length="25" name="Username" not-null="true" unique="true"/>
</property>
<property name="password" type="string">
<column name="Password" not-null="true"/>
</property>
<set inverse="true" name="userRoleses">
<key>
<column name="Username" not-null="true"/>
</key>
<one-to-many class="uk.co.accountablecare.web.orm.generated.UserRoles"/>
</set>
</class>
</hibernate-mapping>

UserRoles.hbm.xml
----------------------
<hibernate-mapping>
<class catalog="accountablecare" name="uk.co.accountablecare.web.orm.generated.UserRoles" table="UserRoles">
<id name="id" type="java.lang.Integer">
<column name="ID"/>
<generator class="identity"/>
</id>
<many-to-one class="uk.co.accountablecare.web.orm.generated.UserRole" fetch="select" name="userRole">
<column length="25" name="Role" not-null="true"/>
</many-to-one>
<many-to-one class="uk.co.accountablecare.web.orm.generated.User" fetch="select" name="user">
<column name="Username" not-null="true"/>
</many-to-one>
</class>
</hibernate-mapping>


UserRole.hbm.xml
---------------------
<hibernate-mapping>
<class catalog="accountablecare" name="uk.co.accountablecare.web.orm.generated.UserRole" table="UserRole">
<id name="role" type="string">
<column length="25" name="Role"/>
<generator class="assigned"/>
</id>
<property name="description" type="string">
<column name="Description" not-null="true"/>
</property>
<set inverse="true" name="userRoleses">
<key>
<column length="25" name="Role" not-null="true"/>
</key>
<one-to-many class="uk.co.accountablecare.web.orm.generated.UserRoles"/>
</set>
</class>
</hibernate-mapping>


Thanks Adam.

I managed to get an answer via the IRC channel from "sebersole" (thanks very much :-)), so I am reproducing the crux of it here in case anyone else has these problems in the future.

Basically the Mappings files that were generated for me by NetBeans were not correct in my case. Hibernate expects to map Foreign Keys onto Primary Keys by default unless otherwise told, in my case the 'Username' field of the 'User' table is not a Primary Key and so the mappings files need some additional information to be able to setup the relationship with the 'UserRoles' table, namely a property-ref attribute for the Username column.

Updated mappings files below -

User.hbm.xml
----------------
<hibernate-mapping>
<class catalog="accountablecare" name="uk.co.accountablecare.web.orm.generated.User" table="User">
<id name="id" type="java.lang.Integer">
<column name="ID"/>
<generator class="identity"/>
</id>
<property name="username" type="string">
<column length="25" name="Username" not-null="true" unique="true"/>
</property>
<property name="password" type="string">
<column name="Password" not-null="true"/>
</property>
<set inverse="true" name="userRoleses">
<key property-ref="username">
<column name="Username" not-null="true"/>
</key>
<one-to-many class="uk.co.accountablecare.web.orm.generated.UserRoles"/>
</set>
</class>
</hibernate-mapping>


And then also on the other end of the Mapping -

UserRoles.hbm.xml
----------------------
<hibernate-mapping>
<class catalog="accountablecare" name="uk.co.accountablecare.web.orm.generated.UserRoles" table="UserRoles">
<id name="id" type="java.lang.Integer">
<column name="ID"/>
<generator class="identity"/>
</id>
<many-to-one class="uk.co.accountablecare.web.orm.generated.UserRole" fetch="select" name="userRole">
<column length="25" name="Role" not-null="true"/>
</many-to-one>
<many-to-one class="uk.co.accountablecare.web.orm.generated.User" fetch="select" name="user" property-ref="username">
<column name="Username" not-null="true"/>
</many-to-one>
</class>
</hibernate-mapping>