c# - Multple Composite PrimaryKey reference as foreign key map in Fluent nHibernate -

this legacy table structure hence no schema modification possible.

patient ------- code - pk hospitalcode - pk - fk hospital.code hospitalgroup - pk - fk hospital.hospitalgroup other fields  hospital ------- code - pk hospitalgroup - pk - fk hospitalgroup.code other fields  department ------- code - pk hospitalcode - pk - fk hospital.code hospitalgroup - pk - fk hospitalgroup.code other fields  diagnose ------- patientcode - pk - fk patient.code hospitalcode - pk - fk hospital.code hospitalgroup - pk - fk hospital.hospitalgroup departmentcode - pk - fk department.code other fields 

the mapping looks following

public class patientmap : classmap<patient> {     public patientmap()     {         compositeid()            .keyproperty(x => x.id, "id")            .keyreference(x => x.hospital, "hospital_id", "hospitalgroup_id")            .keyreference(x => x.hospitalgroup, "hospitalgroup_id");          map(x => x.name);                 } }  public class hospitalmap : classmap<hospital> {     public hospitalmap()     {         compositeid()           .keyproperty(x => x.id, "id")                         .keyreference(x => x.hospitalgroup, "hospitalgroup_id");          map(x => x.name);                 } }  public class hospitalgroupmap : classmap<hospitalgroup> {     public hospitalgroupmap()     {         id(x => x.id).column("id");                     map(x => x.name);                             } }      public class departmentmap : classmap<department> {     public departmentmap()     {        compositeid()            .keyproperty(x => x.id, "id")            .keyreference(x => x.hospital, "hospital_id", "hospitalgroup_id")            .keyreference(x => x.hospitalgroup, "hospitalgroup_id");          map(x => x.name);                           } }  public class diagnosemap : classmap<diagnose> {     public diagnosemap()     {         compositeid()             //.keyreference(x => x.hospital, "hospital_id", "hospitalgroup_id")             //.keyreference(x => x.hospitalgroup, "hospitalgroup_id")             .keyreference(x => x.department, "department_id", "hospital_id", "hospitalgroup_id")             .keyreference(x => x.patient, "patient_id", "hospital_id", "hospitalgroup_id");     } } 

how make fluent mapping such able

patient.diagnoselist[0].department.hospital.code 

currently getting following exception

"identifier mapping has wrong number of columns: examples.firstproject.entities.diagnose type: component[department,patient]"