Trigger Segment

UN/EDIFACT segment-group structuring rule.

Definition

Every segment group begins with a trigger segment whose status, within the group, is always mandatory: its presence opens a new occurrence of the group. Even when the whole group is conditional in the message, its trigger stays mandatory once the group is instantiated.

Origin

This rule follows from the UN/EDIFACT message design guidelines and the ISO 9735 syntax, as applied in the UNTDID Message Implementation Guidelines.

Example in context

In the SG26 group of ORDERS, the LIN segment is the trigger: each LIN opens a new line item.

Related terms

• Segment Group — the unit opened by the trigger.
• SEGMENT — the base unit.