DATABRICKS-SPARK Question 117

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• Chose E0

  - Correct answer : E — `batch_df.write.format("delta").mode("append").save(path)`, which commits the new rows as an additional atomic transaction on top of the existing table history A . Overwrite mode replaces the entire table contents with the new batch, so each hourly run would erase every transaction written in earlier runs rather than accumulating them. B . Errorifexists mode is the default guard against accidentally clobbering an existing table and raises an exception once the path already holds data, so it cannot support repeated hourly writes at all. C . Spark's DataFrameWriter has no automatic key-based merge behavior triggered by omitting the mode; without an explicit mode it falls back to `errorifexists`, which would fail after the first successful write. D . Ignore mode is designed to silently skip a write only when the target already contains data, so it would drop every batch after the first hour instead of accumulating the streaming transactions. E . Append mode commits each new batch as an additional atomic transaction without touching existing rows, so every hour's transactions accumulate on top of the prior history exactly as the job requires.