New sql qyuery format

I've been given a sql query to modify and it has a format that I have not seen before. Here is part of it:

SELECT   PA_.ENQ_OEOrdItem->OEORI_OEORD->OEORD_Adm->DM_ADMNO  AS XX
  FROM PA_EntCont PA_
  WHERE (PA_.ENQ_OEOrdItem->OEORI_ItmMast->ARCIM_Desc IS NOT NULL) OR
        (PA_.ENQ_OEOrdItem->OEORI_ItmMast->ARCIM_Desc IS NULL AND
         PA_.RequestType->REQTYP_Desc IS NOT NULL)

My question is how do you configure the joins to the other tables when only PA_EntCont is defined ? Eg. OEORI_OEORD belongs to another table but only this field is referenced, not its table?