I_PurContrHdrExtReference

@AbapCatalog.sqlViewName: 'IPCHDREXTLINKS'
@AbapCatalog.compiler.compareFilter: true
@AbapCatalog.preserveKey: true
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'External References of Pur Contract Hdr'
@ObjectModel.usageType.serviceQuality: #A
@ObjectModel.usageType.sizeCategory: #L
@ObjectModel.usageType.dataClass: #TRANSACTIONAL
@VDM.viewType: #COMPOSITE
@ClientHandling.algorithm: #SESSION_VARIABLE
define view I_PurContrHdrExtReference
  as select distinct from I_PurContrItemExtReference
{

  key PurchaseContract,
  key LinkType,
      PurgDocExternalReference,
      cast(case
      when PurgDocExternalReference is not initial
      then
        case
          when PurgDocExternalSystem is not initial
          then
            concat('External (', concat(PurgDocExternalSystem, ')'))
          else
            'External'
        end
      else
        case
          when PurgDocExternalReference is not initial
          then 'Internal'
          else ''
        end
      end         as mmpur_ext_system) as PurgOutlineAgrmtExtSystID,
      PurgDocExternalSystem,
      PurgDocExtReferenceNodeType

}