Mapping same classes to different table structure

Cue · **Joined:** Tue May 04, 2004 6:15 am **Posts:** 51

Hi there,

Using Hiberante 2.1.3

I have the following mappings

agenciesLocations.hbm.xml

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping package="gr.forthnet.openseas.models">   

<class name="Location" table="agencies_cities_counties" polymorphism="explicit"> 
        <id name="abbreviation"  column="county_en"  type="java.lang.String"  unsaved-value="null"  length="32"> 
            <generator class="hilo"/> 
        </id> 

        <property name="name" column="county_gr_en" not-null="true"/>
        
        <bag name="destinations" cascade="all" inverse="false" lazy="false">
           <key column="county_en" />
           <one-to-many class="Area" />
        </bag>
</class>

<class name="Area" table="agencies_cities_counties"> 
   <id name="abbreviation"  column="city_en"  type="java.lang.String"  unsaved-value="null"  length="32"> 
       <generator class="hilo"/>
    </id> 

    <property name="name" column="city_gr_en" not-null="true"/>
        
    <many-to-one name="parent" class="Location" column="county_en" />
</class>
</hibernate-mapping>

locations.hbm.xml

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping package="gr.forthnet.openseas.models">   

<class name="Location" table="destinations" polymorphism="explicit"> 
        <id name="abbreviation"  column="dabbr"  type="java.lang.String"  unsaved-value="null"  length="32"> 
            <generator class="hilo"/> 
        </id> 

        <property name="name" column="dname" not-null="true"/>
        
        <bag name="destinations" cascade="all" inverse="false" lazy="false">
           <key column="dabbr" />
           <one-to-many class="Area" />
        </bag>
</class>

<class name="Area" table="areas"> 
   <id name="abbreviation"  column="aabbr"  type="java.lang.String"  unsaved-value="null"  length="32"> 
       <generator class="hilo"/>
    </id> 

    <property name="name" column="aname" not-null="true"/>
        
    <many-to-one name="parent" class="Location" column="dabbr" />
</class>
</hibernate-mapping>

Ofcourse I get a duplicate import error on this.

How can i make the above mappings and how do I distinguish them in HQL?

Thanks in advance

michael · **Posted:** Tue May 11, 2004 7:59 am

You can use two SessionFactories, but otherwise mapping one class twice in different ways is not possible.

Cue · **Joined:** Tue May 04, 2004 6:15 am **Posts:** 51

So do I have to I remove any mappings in the configuration file and add them manually with the Configuration class?

michael · **Posted:** Tue May 11, 2004 8:42 am

You can also use two different configuration files.

Cue · **Joined:** Tue May 04, 2004 6:15 am **Posts:** 51

Yeah, but wouldnt that be obsolete? Having two configuration files with the same settings for the db and different mappings :/

PS. I just realised 'who you are' by clicking the www link on ur profile! Nice 2 meet u m8 :D

michael · **Posted:** Tue May 11, 2004 9:07 am

It's your choice of course :) You can probably also use XML Entity includes in your config files to include the similar parts.

Cue · **Joined:** Tue May 04, 2004 6:15 am **Posts:** 51

Hm... its going to be a little more tricky than I thought at first.

I can use one xml file for the common parts of the configuration as you mentioned, but since the DTD for hiberante.cfg.xml isn't specifying a separate tag for the database configuration section, when I import the common part I will get a validation error. Unless I'm missing smth.

If I instead decide to simply remove all the mapping declarations from the cfg file, then I have to add them in Java and that means hardcoding the filenames. Not elegant, but it works...