Key for Integration ODS for 2LIS_12_VCHDR AND 2LIS_12_VCITM

Hey Gurus,

What would be the key for integration ODS of Delivery Header 2LIS_12_VCHDR and Delivery Item 2LIS_12_VCITM ???

1) If I make Delivery number as my key then item details will be over written.

2) If I make both Delivery number and delivery item number as my key, then how about the records which gets uploaded by HDR datasource. Those records will get Balnk value for ITEM NUMBER primary Key.

PLEASE CORRECT ME IF I AM WRONG.

replies are awarded for sure.

EXPERTS PLEASE HELP ME OUT.

Thanks