We have the following mapping, which works fine with Hibernate 3.0.5:



However, it no longer works in 3.2CR3. I get a NullPointerException from within Hibernate. I have jack'd with the Hibernate Code, and modified the SQLQueryReturnProcessor::addCollection(String, String, Map ) method to add the following conditional: || collectionPersister.isManyToMany(), as below to fix the Exception:



This results in an SQL Statement that has all the columns from the look-up table, as well as the table containing the related entity. My custom SQL is only returning the columns from the lookup-table.

It seems that the following block of code in the SQLQueryParser::resolveCollectionProperties(String, String) method is not correct:



In my case, I would be happy if it just returned selectFragment.

I have also tried jackin' with the code to just return selectFragment for the many-to-many case, but then Hibernate is not able to parse the results, as it is trying to find columns in the result set that are part of the related entity, not the lookup-table which is what is being queried.

Why is 3.2CR3 acting differently than 3.0.5? It really seems like many-to-many relationships and sql-query/load-collection are not supported anymore.

I would really like to use 3.2CR3, because of the advertized fix: HHH-1792 which I need to have as I am using IBM UDB 7.2 as my database; and trying to use stored procedures to implement the INSERT/DELETE functionality on the lookup table in the above mapping.

There were significant changes to how native sql queries are handled in 3.2.0.cr3: http://opensource.atlassian.com/project ... elog-panel

I have changed my test environment to change the lookup table for the many-to-many join to work with normal Hibernate schematics; added extra key column, LC_MANF_UPC_C to the PACK_LINE_CODES table. ( In production environment this column is not present, and the MANF_UPC_C column is used in both foreign keys of the many-to-many relationship. )

When I run my app, the following SQL is generated:



So, I can see that my custom SQL is not correct as shown in the previous post.

However, even if I change the query to look like this, I still think I will get the NullPointerException from Hibernate because of the missing conditional in the SQLQueryReturnProcessor::addCollection(String, String, Map ) method as noted in the previous posting.

I have gotten Hibernate 3.2CR3 to work with my modified sql-query mapping; but only after making the following change to SQLQueryReturnProcessor::addCollection(String, String, Map ).

The conditional, needs to also check for many-to-many in order to get the columns for the fetch join to work correctly:

Added code: || collectionPersister.isManyToMany()



Without the code change, Hibernate will throw a NullPointerException in SQlQueryParser::resolveProperties(String, String ) since it can't find an entity persister.

Should this be reported as a bug?

I see this question is dated almost a year back ago. I am currently using the lastest release and facing the same NullPointerException. Were you able to figure out an alternative solution other than modifying the under lying code?

In the end we convinced our DBA's that the way the data relationship was modeled in the DB was wrong, and we could use more standard mapping with the version of Hibernate we were currently using ( 3.0 ).

If you are getting the same issue, I would press to see if this needs to be reported as a Hibernate bug.

I was getting that error because of the alias name. Once I added a return alias name it ran fine but with wrong data.

I tried to use loader query to load my mapping for many-to-many relationship as i wanted only a few columns from the final associated class and not the huge pile of data. I must have surely mapped it wrong as during loading it completely missed the mapping and passed the initial value as the input parameter.

Following is the mapping for your reference.

[b] Employee
<class name="Employee">
.....
.....
<bag name="messages" table="MSG_DETAIL" inverse="true">
<key column="EMP_ID"/>
<many-to-many class="Message" column="MSG_ID" />
</class>


Message
<class name="Message">
.....
.....
<bag name="employees" table="MSG_DETAIL">
<key column="MSG_ID"/>
<many-to-many class="Employee"column="EMP_ID"/>
<loader query-ref="loadEmployees" />
</bag>
</class>


<sql-query name="loadEmployees">
<return alias="EMP" class="Employee"/>
<load-collection alias="EMP"
role="Message.employees" />
SELECT
EMP.EMP_ID AS {emp.emplId},
EMP.ACTIVE_IND AS {emp.activeIndicator},
EMP.FIRST_NAME AS {emp.firstName},
EMP.JOB_TITLE AS {emp.jobTitle},
EMP.LAST_NAME AS {emp.lastName},
EMP.MIDDLE_INITIAL AS {emp.middleInitial}
FROM
Employee EMP
WHERE EMP_ID = :EMP_ID
</sql-query>

[/b]

I wasnt sure how to load the collection with a join query to msg_detail table as there is no mapping for the table for hibernate to understand.