Hi,
There is a table Item like,
code,name
01,parent1
02,parent2
0101,child11
0102,child12
0201,child21
0202,child22
Create a java object and hbm xml to map the table.The Item.parent is a Item whose code is equal to the first two characters of its code :
class Item{
String code;
String name;
Item parent;
List<Item> children;
.... setter/getter....
}
<hibernate-mapping>
<class name="Item" table="Item">
<id name="code" length="4" type="string">
<generator class="assigned" />
</id>
<property name="name" column="name" length="50" not-null="true" />
<many-to-one name="parent" class="Item" not-found="ignore">
<formula>
<![CDATA[
(select i.code,r.name from Item i where (case length(code) when 4 then i.code=SUBSTRING(code,1,2) else false end))
]]>
</formula>
</many-to-one>
<bag name="children"></bag>
</class>
</hibernate-mapping>
I try to use formula to define the many-to-one relationship,but it doesn't work!Is there something wrong?Or is there other method?
Thanks!
ps,I use mysql database.
