Relationship to the PM's Parent records, used to find the parent record for a given PM. (pm.pmnum = pm.parent). The resulting set will contain zero or one record.
Razmerje do zapisov Parent za PV, ki se uporablja za iskanje zapisa nadrejenca za dano PV. (pm.pmnum = pm.parent). Nabor rezultatov bo vseboval nič zapisov ali enega samega.