Mapping a Joined String

stephan.rossouw · **Joined:** Fri Oct 26, 2007 11:01 am **Posts:** 3

Hi there,

I am sort of new to hibernate. I would like to know how to map a certain property. I have a String property in my Person class that is split into a different table.

Heres my tables:

tbl_Person
========
ID
NAME
ADDRESS_ID

tbl_Address
=========
ID
ADDRESS

This is my class:

Class Person
String NAME
String ADDRESS

How would you map the address relationship on the person class?

vw729 · **Joined:** Wed Aug 25, 2004 7:40 pm **Posts:** 65

There are a few approaches in this regard.

If you want to set up the address as an entity where you need a table with a unique id as you have set up, you can use one-to-one mapping or many-to-one mapping. Please read the reference documentation for more detailed information.

An easy way may be to set up the address as a component which you don't need a table if you only need one address per person.

HTH

stephan.rossouw · **Joined:** Fri Oct 26, 2007 11:01 am **Posts:** 3

Hi,

Thanks for the reply. This is actually a legacy system that I cannot change the database or the java source. I will have to sort this out with mappings. I am a bit fuzy on how to use a one-to-one to map to a string and not a custom class.

I would do this:

Code:

<hibernate-mapping>
<class name="Person" table="tbl_Person">

        <id name="id"
            type="java.lang.Integer"
            column="id"
            unsaved-value="0">
            
            <generator class="identity" />
        </id>

        <property name="name"
                  type="java.lang.String"
                  column="name"
                  not-null="true"
                  length="30"/>

       <one-to-one
         name="ADDRESS"
         foreign-key="ADDRESS_ID"
         cascade="save-update"/>

   </class>
</hibernate-mapping>

This doesnt work. How would hibernate know what column I want to put in that ADDRESS field? How would hibernate know what ID column it should match? Am I missing something huge here?

stephan.rossouw · **Joined:** Fri Oct 26, 2007 11:01 am **Posts:** 3

I tried everything I can think of, is there no way to map a String to a class that sits in another table?

sethrohit1977 · **Joined:** Mon Jan 22, 2007 10:32 am **Posts:** 101

You can create a property with formula column that can bring the value of address from underlying table. But this resolve only the reading part.

If you can change the java souce (of person.java) then another option could be to have a read-write mapping for address with another name and the setter / getter for address can use the setter / getter of this property under the covers.

Another approach could be to implement address as a userType.

HTH