Hibernate - Query multiple tables with one hibernate-mapping

Question

I do have a hibernate mapping which looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="org.lwl.anlei.bl.model.imp">  

   <class name="PersonFo">
     <id name="id" type="integer"/>     
     <property name="name" type="string"/>
     <property name="info" type="string"/>
   </class> 

  <sql-query name="person1">
    <return alias="gb" class="PersonFo"/>
    SELECT id          as {gb.id},
           name        as {gb.name},
           info        as {gb.info}
    FROM   table
    WHERE  field1 = :param
  </sql-query>

  <sql-query name="person2">
    <return alias="gb" class="PersonFo"/>
    SELECT id          as {gb.id},
           second_name as {gb.name},
           whatever    as {gb.info}
    FROM   table
    WHERE  field2 = :param
  </sql-query>

</hibernate-mapping>

This is the simplyfied hbm of what I do have. In Java I am getting my data in this way, with the "getQueryName":

List<Person> myPersons =
    session.getNamedQuery("person1").setString("param", "important text").list();

Now I have to use views, instead of these querys. I know, I could simply write "SELECT xxx FROM view_person1" and "SELECT xxx FROM view_person2" into the sql-querys, but I would prefer to use something like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="org.lwl.anlei.bl.model.imp">  

   <class name="PersonFo" 
    table="view_person1"
    entity-name="view_person1" >
     <id name="id" column="id" type="integer"/>     
     <property name="name" column="name" type="string"/>
     <property name="info" column="info" type="string"/>
   </class> 

   <class name="PersonFo" 
    table="view_person2"
    entity-name="view_person2" >
     <id name="id" column="id" type="integer"/>     
     <property name="name" column="name" type="string"/>
     <property name="info" column="info" type="string"/>
   </class> 

</hibernate-mapping>

In another example, I saw how to save data via hibernate this way. Map Two Identical tables ( same schema...) to same entity in Hibernate

They simply used:

_session.Save("view_person1", xxxx) 
_session.Save("view_person2", xxxx)

But, how do I QUERY data? Is there something like:

List<Person> myPersons =
    session.getNamedEntity("view_person2").list();

Help will be very appriciated! Thanks!

user3487063 · Accepted Answer · 2014-10-01 16:17:34Z

1

Use polymorphism="explicit" to differentiate your named entities:

<class name="PersonFo" 
    table="view_person1"
    entity-name="view_person1" polymorphism="explicit" >
     <id name="id" column="id" type="integer"/>     
     <property name="name" column="name" type="string"/>
     <property name="info" column="info" type="string"/>
   </class> 

   <class name="PersonFo" 
    table="view_person2"
    entity-name="view_person2" >
     <id name="id" column="id" type="integer"/>     
     <property name="name" column="name" type="string"/>
     <property name="info" column="info" type="string"/>
   </class>

and query your named entities like below:

List list1 = session.createQuery("from view_person1").list();
List list2 = session.createQuery("from view_person2").list();

answered Oct 1, 2014 at 16:17

user3487063

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1 Comment

Stix Over a year ago

I'm gonna test that. Thanks in advance!

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