# PEPPOL-T01-R001

Source: https://xmlvalid.com/rules/PEPPOL-T01-R001

> Each order line SHALL have a document line identifier that is unique within the order.

- Level: error
- Rule sets: Peppol Order rules 3.7
- Context: `cac:OrderLine/cac:LineItem`
- Test: `count(key('k_lineId',cbc:ID)) = 1`

Validate a document against these rules: https://xmlvalid.com/validate