public boolean hasValidKeyRelation() { if (null == m_relationships || m_relationships.size() != 1) return false; SemanticElementRelationship r = m_relationships.get(0); MdmiDatatype dt = r.getRelatedSemanticElement().getDatatype(); if (!dt.isPrimitive()) return false; DTSPrimitive d = (DTSPrimitive) dt; return DTSPrimitive.STRING.equals(d); }