Microsoft Fabric Data Engineer Associate DP-700 Practice Question

Delta Lake offers ACID transactions and the MERGE INTO command, which performs atomic upserts based on key columns. By creating a temporary view that assigns ROW_NUMBER() over (PARTITION BY OrderID, LineNumber ORDER BY EventDate DESC) and filtering for the first row, you keep just the newest version of each order line. Merging this view into sales.Order updates existing rows and inserts new ones, so repeated notebook runs remain idempotent. COPY INTO does not enforce primary-key uniqueness, OPTIMIZE ZORDER BY only reorders data without removing duplicates, and a TRUNCATE followed by INSERT reloads all data and discards late-arriving rows.