I try the following Query:


proc.coDriver may be null, but the result does not contain any row where the proc.coDriver is null! They are filtered out! proc.transportDevice, proc.driver and proc.coDriver are all mapped Objects.

Hibernate version: Hibernate 2.1.8

Mapping documents:

<?xml version="1.0" encoding="UTF-8"?>

<!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.optitrans.ejb.model.TransportProcess"
table="OT_Transportvorgang"
dynamic-update="false"
dynamic-insert="false"
select-before-update="false"
optimistic-lock="version"
>

<id
name="id"
column="ID"
type="java.lang.Long"
unsaved-value="null"
>
<generator class="seqhilo">
<!--
To add non XDoclet generator parameters, create a file named
hibernate-generator-params-TransportProcess.xml
containing the additional parameters and place it in your merge dir.
-->
</generator>
</id>

<version
name="version"
type="java.util.Date"
column="Version"
access="property"
unsaved-value="undefined"
/>

<many-to-one
name="coDriver"
class="com.optitrans.ejb.model.Employee"
cascade="none"
outer-join="auto"
update="true"
insert="true"
access="property"
column="ID_Mitarbeiter_Beifahrer"
not-null="false"
/>

<many-to-one
name="driver"
class="com.optitrans.ejb.model.Employee"
cascade="none"
outer-join="auto"
update="true"
insert="true"
access="property"
column="ID_Mitarbeiter_Fahrer"
not-null="true"
/>

<property
name="endLastTransport"
type="java.util.Date"
update="true"
insert="true"
access="property"
column="EndeLetzterTransport"
/>

<property
name="startFirstTransport"
type="java.util.Date"
update="true"
insert="true"
access="property"
column="BeginnErsterTransport"
/>

<set
name="transportTasks"
lazy="true"
inverse="false"
cascade="none"
sort="unsorted"
>

<key
column="ID_Transportvorgang"
>
</key>

<one-to-many
class="com.optitrans.ejb.model.TransportTask"
/>

</set>

<many-to-one
name="transportDevice"
class="com.optitrans.ejb.model.TransportDevice"
cascade="none"
outer-join="auto"
update="true"
insert="true"
access="property"
column="ID_Transportmittel"
not-null="false"
/>

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

</class>

</hibernate-mapping>


Database: Firebird 1.5.2.4731

The generated SQL (show_sql=true):
maybe not so interesting...
**************************************
select transportd1_.ID as ID0_, employee2_.ID as ID1_, employee3_.ID as ID2_, transportd1_.Version as Version0_, transportd1_.Beschreibung as Beschrei3_0_, transportd1_.IstBenutzerdefiniert as IstBenut4_0_, transportd1_.Name as Name0_, transportd1_.ID_Transportmitteltyp as ID_Trans6_0_, transportd1_.Ausmustern as Ausmustern0_, transportd1_.Sortierschluessel as Sortiers8_0_, employee2_.Version as Version1_, employee2_.ID_Adresse as ID_Adresse1_, employee2_.Nachname as Nachname1_, employee2_.Geburtsname as Geburtsn5_1_, employee2_.Vorname as Vorname1_, employee2_.Kurzname as Kurzname1_, employee2_.Spitzname as Spitzname1_, employee2_.IstWeiblich as IstWeibl9_1_, employee2_.Geburtsdatum as Geburts10_1_, employee2_.TelFest as TelFest1_, employee2_.TelMobil as TelMobil1_, employee2_.Email as Email1_, employee2_.Bis as Bis1_, employee3_.Version as Version2_, employee3_.ID_Adresse as ID_Adresse2_, employee3_.Nachname as Nachname2_, employee3_.Geburtsname as Geburtsn5_2_, employee3_.Vorname as Vorname2_, employee3_.Kurzname as Kurzname2_, employee3_.Spitzname as Spitzname2_, employee3_.IstWeiblich as IstWeibl9_2_, employee3_.Geburtsdatum as Geburts10_2_, employee3_.TelFest as TelFest2_, employee3_.TelMobil as TelMobil2_, employee3_.Email as Email2_, employee3_.Bis as Bis2_ from OT_Transportvorgang transportp0_, OTT_Transportmittel transportd1_, OTM_Mitarbeiter employee2_, OTM_Mitarbeiter employee3_ where transportp0_.ID_Transportmittel=transportd1_.ID and transportp0_.ID_Mitarbeiter_Fahrer=employee2_.ID and transportp0_.ID_Mitarbeiter_Beifahrer=employee3_.ID
**************************************

I really think this is not correct. The result should contain null values for the rows where certain attributes are null. Maybe the return type cannot hold the null values? At least, this should be clearly documented. This is like an invisible where-clause