diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/IRelationshipTypeDAO.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/IRelationshipTypeDAO.java
index df2b38365efcdaa98943bf99a4737ea1f7902efe..3269ee56b6ef77277e7c07243238a137471120af 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/IRelationshipTypeDAO.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/IRelationshipTypeDAO.java
@@ -29,4 +29,6 @@ public interface IRelationshipTypeDAO extends IGenericDAO<RelationshipTypePE>
      */
     public RelationshipTypePE tryFindRelationshipTypeByCode(String code);
 
+    public Long getRelationshipTypeId(String code);
+
 }
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/RelationshipTypeDAO.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/RelationshipTypeDAO.java
index 86ff093d4cbb28ab15ac5ea21874dc3e8e4b1b05..65b32059c12c1787d672a125db4f95ea1fa1389b 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/RelationshipTypeDAO.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/RelationshipTypeDAO.java
@@ -69,7 +69,7 @@ public class RelationshipTypeDAO extends AbstractGenericEntityDAO<RelationshipTy
         return type;
     }
 
-    private synchronized Long getRelationshipTypeId(String code)
+    public synchronized Long getRelationshipTypeId(String code)
     {
         if (relationshipTypeIdsMap == null)
         {
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/SampleRelationshipDAO.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/SampleRelationshipDAO.java
index 58803d51c768200e1f7638f14a7f73682aae0c31..2f9df6bf8b9e6b41b0d3264f221ace46a17b526b 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/SampleRelationshipDAO.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/server/dataaccess/db/SampleRelationshipDAO.java
@@ -36,17 +36,17 @@ public class SampleRelationshipDAO extends AbstractGenericEntityDAO<SampleRelati
     }
 
     public List<SampleRelationshipPE> listSampleParents(List<Long> childrenTechIds) {
-        RelationshipTypePE relationshipType = relationshipTypeDAO.tryFindRelationshipTypeByCode(BasicConstant.PARENT_CHILD_INTERNAL_RELATIONSHIP);
+        Long typeId = relationshipTypeDAO.getRelationshipTypeId(BasicConstant.PARENT_CHILD_INTERNAL_RELATIONSHIP);
         final DetachedCriteria criteria = DetachedCriteria.forClass(SampleRelationshipPE.class);
-        criteria.add(Restrictions.eq("relationship.id", relationshipType.getId()));
+        criteria.add(Restrictions.eq("relationship.id", typeId));
         criteria.add(Restrictions.in("childSample.id", childrenTechIds));
         return cast(getHibernateTemplate().findByCriteria(criteria));
     }
 
     public List<SampleRelationshipPE> listSampleChildren(List<Long> parentTechIds) {
-        RelationshipTypePE relationshipType = relationshipTypeDAO.tryFindRelationshipTypeByCode(BasicConstant.PARENT_CHILD_INTERNAL_RELATIONSHIP);
+        Long typeId = relationshipTypeDAO.getRelationshipTypeId(BasicConstant.PARENT_CHILD_INTERNAL_RELATIONSHIP);
         final DetachedCriteria criteria = DetachedCriteria.forClass(SampleRelationshipPE.class);
-        criteria.add(Restrictions.eq("relationship.id", relationshipType.getId()));
+        criteria.add(Restrictions.eq("relationship.id", typeId));
         criteria.add(Restrictions.in("parentSample.id", parentTechIds));
         return cast(getHibernateTemplate().findByCriteria(criteria));
     }
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java
index 13d3991caec2a158317828f0301bfcf1219c48a9..5e8a2400139581dec0ae19820dbd0545888f5ad5 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java
@@ -43,9 +43,10 @@ import javax.persistence.Version;
 import javax.validation.constraints.NotNull;
 import javax.validation.constraints.Pattern;
 
-import ch.ethz.sis.openbis.generic.server.asapi.v3.executor.relationship.IGetRelationshipIdExecutor;
 import ch.systemsx.cisd.openbis.generic.server.CommonServiceProvider;
-import ch.systemsx.cisd.openbis.generic.shared.basic.*;
+import ch.systemsx.cisd.openbis.generic.shared.basic.BasicConstant;
+import ch.systemsx.cisd.openbis.generic.shared.basic.IIdHolder;
+import ch.systemsx.cisd.openbis.generic.shared.basic.IIdentityHolder;
 import org.apache.commons.lang3.builder.EqualsBuilder;
 import org.apache.commons.lang3.builder.HashCodeBuilder;
 import org.apache.commons.lang3.builder.ToStringBuilder;