mapping pojo property:no relation between db tables [SOLVED]

entaroadun7 · **Joined:** Thu Feb 26, 2009 2:22 pm **Posts:** 9

Hi, I have two pojo i.e.

class A
{
int a_id;
String name;
Timestamp a_time;
}

class B
{
int b_id;
int x;
Timestamp b_time;
A a; <<<<<<<<<<<<<<<<< how to initialize 'a' through mapping?
}

When I get from db pojo 'B' I want to initialize (through mapping) property 'A' in pojo 'B' by special sql query (i.e. from A as a when a.a_time = b.b_time), but there is no relation between database tables (PK, FK). Is it possiable?

littypreethkr · **Posted:** Fri Feb 27, 2009 1:37 am

You can map the relation like this.

Code:

   <class name="A">
      <id name="a_id" column="A_ID" type="int" unsaved-value="0">
         <generator class="native" />
      </id>
      
      <property name="name" />
      
      <property name="a_time" column="A_TIME" unique="true"/>
   </class>

   <class name="B">
      <id name="b_id" column="B_ID" type="int" unsaved-value="0">
         <generator class="native" />
      </id>
      
      <property name="x" />
      
      <many-to-one name="a" class="A" property-ref="a_time" column="B_TIME" fetch="join"></many-to-one>
   </class>

Please note <property name="a_time" unique="true"/>
The referring property should be unique as this is a many-to-one relation. Your B has only one related A.

entaroadun7 · **Joined:** Thu Feb 26, 2009 2:22 pm **Posts:** 9

Thanks for replay. But is it possible to do this with query ? In case of one property needs value(s) from 3rd table i.e. from A as a when a.a_time = b.b_time and a.name = (select c.name form C where c.x = b.x) ?
ps. 'a' unique when a.a_time = b.b_time and a.name = (select c.name form C where c.x = b.x). Thx

littypreethkr · **Posted:** Mon Mar 02, 2009 1:38 am

I think you can use formula to map such queries to properties. Didnt use it, but u can try searchng for tht.

entaroadun7 · **Joined:** Thu Feb 26, 2009 2:22 pm **Posts:** 9

Thanks, 'formula' solved the problem.