XMLDirectMapping validationMapping = new XMLDirectMapping();
validationMapping.setAttributeName("m_validation");
validationMapping.setConverter(new EnumTypeConverter(validationMapping, IdValidation.class, false));
validationMapping.setXPath("@validation");
descriptor.addMapping(validationMapping);
XMLCompositeCollectionMapping columnsMapping = new XMLCompositeCollectionMapping();
columnsMapping.setAttributeName("m_columns");
columnsMapping.setReferenceClass(ColumnMetadata.class);
columnsMapping.setXPath("orm:column");