When a MERGE statement with a MERGE WHEN MATCHED clause executes, the system activates triggers defined on UPDATE or DELETE operations.
When a MERGE statement with a MERGE WHEN NOT MATCHED clause executes, the system activates triggers defined on INSERT operations.
The order of activation of UPDATE and INSERT triggers is the same as the order of the MERGE WHEN MATCHED and MERGE WHEN NOT MATCHED clauses in the MERGE request.
The following orders of operations apply to MERGE operations on source tables that have multiple rows. Assume for all cases that both updates to existing rows in the target table and inserts of new rows into the target table occur without incident.