Suppose, we have 3 entities
{code:xml}
<hibernate-mapping>
<class name="AEntity" table="A" abstract="true">
<id name="id" >
< column name ="ID"/>
</id>
<joined-subclass table="Aa" name="AaEntity">
<key column="key"/>
<many-to-one name="b" class="BEntity">
<column name="B_ID"/>
</many-to-one>
</joined-subclass>
<joined-subclass table="Ab" name="AbEntity">
<key column="key"/>
<many-to-one name="b" class="BEntity">
<column name="B_ID"/>
</many-to-one>
</joined-subclass>
</class>
</hibernate-mapping>
{code}
{code:xml}
<hibernate-mapping>
<class name="Parent" table="parent">
<id name="id">
<column name="ID"/>
</id>
<many-to-one name="a" class="AEntity">
<column name="a_ID" />
</many-to-one>
</class>
</hibernate-mapping>
{code}
{code:xml}
<hibernate-mapping>
<class name="BEntity" table="B">
<id name="id">
<column name="ID"/>
</id>
</class>
</hibernate-mapping>
{code}
Then, we make criteria request
{code:java}
Criteria criteria = session.createCriteria(Parent.class);
criteria.createAlias("a","a");
criteria.createAlias("a.b","b");
criteria.list();
{code}
And get next sql
{code:sql}
select this_.ID as ID1_5_3_,
this_.a_ID as a2_5_3_,
a1_.ID as ID1_2_0_,
a1_.B_ID as B2_2_0_,
a1_1_.B_ID as B2_0_0_,
a1_2_.B_ID as B2_1_0_,
case when a1_1_.key is not null then 1 when a1_2_.key is not null then 2 when a1_.ID is not null then 0 end as clazz_0_,
b2_.ID as ID1_3_1_,
b2_.C_ID as C2_3_1_,
b2_.ID as ID1_3_2_,
b2_.C_ID as C2_3_2_
from parent this_
inner join A a1_ on this_.a_ID=a1_.ID
left outer join Aa a1_1_ on a1_.ID=a1_1_.key
left outer join Ab a1_2_ on a1_.ID=a1_2_.key
inner join B b2_ on a1_1_.B_ID=b2_.ID
inner join B b2_ on a1_2_.B_ID=b2_.ID
{code}
We can see that B table joins two times and have same name b2_. Is it bug? And how make two joins but with different name of B table. Okay? |
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