I have run into an issue using the Criteria API that I believe to be
the same as discussed in this thread:
http://forum.hibernate.org/viewtopic.php?t=934119
and this JIRA issue:
http://opensource.atlassian.com/projects/hibernate/browse/HB-1206
I am trying to perform an outer join using Criteria, but as soon
as I introduce an alias via createAlias(), the left outer joins are
forced to inner joins...
Code between sessionFactory.openSession() and session.close():
Code:
System.out.println(
"size without aliases: " +
s.createCriteria(Foo.class)
.list()
.size());
System.out.println(
"size with aliases: " +
s.createCriteria(Foo.class)
.createAlias("bar", "BAR")
.createAlias("baz", "BAZ")
.list()
.size());
The generated SQL (show_sql=true):Debug level Hibernate log excerpt:Code:
Hibernate:
select
this.id as id2_,
this.bar_id as bar_id2_,
this.baz_id as baz_id2_,
bar1_.id as id0_,
bar1_.name as name0_,
baz2_.id as id1_,
baz2_.name as name1_
from t_foo this
left outer join t_bar bar1_ on this.bar_id=bar1_.id
left outer join t_baz baz2_ on this.baz_id=baz2_.id
where 1=1
size without aliases: 3
Hibernate:
select this.id as id2_,
this.bar_id as bar_id2_,
this.baz_id as baz_id2_,
BAR.id as id0_,
BAR.name as name0_,
BAZ.id as id1_,
BAZ.name as name1_
from t_foo this
inner join t_bar BAR on this.bar_id=BAR.id
inner join t_baz BAZ on this.baz_id=BAZ.id
where 1=1
size with aliases: 0
(some of the foreign keys are null, let me know if the insert statements would be useful)
I've searched the forums and source looking for clues and spent
a few hours with a debugger, but I still can't tell if this behavior
is intentional or if there is a workaround. The forum post and JIRA
comments linked above suggests it might be intentional, but the
replies were fairly brief and didn't give any explanation.
The Criteria API suits the code I am writing better than HQL. Before
I dump my Criteria code and reimplement it in HQL, is there anyone
out there willing to elaborate on why aliases affect the join types?
Is this a feature? Is there a reasonable way to change the behavior
and would a patch that does so be accepted?
Thank you in advance for any replies and, to the developers, thank you
for sharing Hibernate with us.
(Remainder of requested information below signature.)
--Brad
Hibernate version: 2.1.6
Mapping documents:Code:
<hibernate-mapping>
<class name="eg.Foo" table="t_foo">
<id name="id"><generator class="assigned"/></id>
<!--
<property name="barId" column="bar_id"/>
<property name="bazId" column="baz_id"/>
-->
<many-to-one name="bar" class="eg.Bar" column="bar_id"/>
<many-to-one name="baz" class="eg.Baz" column="baz_id"/>
</class>
<class name="eg.Bar" table="t_bar">
<id name="id"><generator class="assigned"/></id>
<property name="name"/>
</class>
<class name="eg.Baz" table="t_baz">
<id name="id"><generator class="assigned"/></id>
<property name="name"/>
</class>
</hibernate-mapping>
Not applicable.
Name and version of the database you are using:
Oracle 9i
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