Q: 18
Which of the following commands can be used to write data into a Delta table while avoiding the
writing of duplicate records?
Options
Discussion
C is the one that handles deduplication since MERGE lets you match on keys and only updates or inserts if needed. APPEND or INSERT could just write duplicates straight in. Pretty sure C is right here, but curious if anyone sees a use case I missed.
Why do Databricks questions always sneak in MERGE for this? C
C not D. APPEND (D) doesn't check for duplicates at all, that's a common trap here. Pretty sure MERGE is what prevents duplicate inserts, unless you misconfigure the match. Feel free to correct me if I'm missing something.
Merge is the way to avoid dups since it does upserts based on match conditions. C here, since things like APPEND or INSERT just slam new rows in without checking. Almost positive C, unless someone knows a weird edge case.
Not A, C here. MERGE lets you match and update or insert only if not present, so it avoids duplicates. The rest just add or drop data without checking for existing rows, at least from what I've seen in exam dumps.
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