Help with Partial MongoDB Update via Azure Data Factory Data Flow

In ADF Data Flows you can handle this by using a Derived Column to update the array: set status to "SENT" with an iif expression, and use arrayUnion() to append the new object with event, description, timestamp, and system into nested_array. In the MongoDB Sink, set the write behavior to update with _id as the key and choose update instead of replace so only those fields are modified while the rest of the document (like root_field and numeric_value) stays intact.