I know it has to be a really basic hibernate question, well, my problem is that I have a pojo like this one: class Pojo { Integer id; TypeA foo; TypeB zas; ... getters and setters.... } class TypeA { Integer id; String description; ... getters and setters.... } class TypeB { Integer id; String description; ... getters and setters.... } and I have two mappings: <hibernate-mapping > <class name="Pojo" table="pojo_table"> <id column="pojo_id" name="id" type="int" unsaved-value="0"> <generator class="native" /> </id> <property name="foo" class="TypeA" column="pojo_foo" /> <property name="zas" class="TypeB" column="pojo_zas" /> </class> <class name="TypeA" table="typea_table"> <id column="typea_id" name="id" type="int" unsaved-value="0"> <generator class="native" /> </id> <property name="description" class="string" column="description" /> </class> </hibernate-mapping> But as you can see there is no TypeB mapping, because this value is being set in the service layer by a web service query, but I just want to persist the id of the returned object (TypeB). thus I want something like to transform cell values for TypeB (the id) and the object itself. public class TypeBResolver{ public Integer getAsCellValue() { TypeB d = (TypeB) getValue(); if (d == null) { return null; } return d.getId(); } public TypeB resolvCellValueForPojo(Integer s) { if (s != null) { return typeBService.getB(s); } else {return null} } -- Jaime Hablutzel (tildes omitidas intencionalmente)