Deal of The Day! Hurry Up, Grab the Special Discount - Save 25% - Ends In 00:00:00 Coupon code: SAVE25
Welcome to Pass4Success

- Free Preparation Discussions
Mail Us support@pass4success.com
Location
Mob_nav_barsMENU

Databricks Exam Databricks Certified Data Engineer Professional Topic 2 Question 34 Discussion

Actual exam question for Databricks's Databricks Certified Data Engineer Professional exam
Question #: 34
Topic #: 2
[All Databricks Certified Data Engineer Professional Questions]

A data engineer is configuring a pipeline that will potentially see late-arriving, duplicate records.

In addition to de-duplicating records within the batch, which of the following approaches allows the data engineer to deduplicate data against previously processed records as it is inserted into a Delta table?

Show Suggested Answer Hide Answer
Suggested Answer: C

To deduplicate data against previously processed records as it is inserted into a Delta table, you can use the merge operation with an insert-only clause. This allows you to insert new records that do not match any existing records based on a unique key, while ignoring duplicate records that match existing records. For example, you can use the following syntax:

MERGE INTO target_table USING source_table ON target_table.unique_key = source_table.unique_key WHEN NOT MATCHED THEN INSERT *

This will insert only the records from the source table that have a unique key that is not present in the target table, and skip the records that have a matching key. This way, you can avoid inserting duplicate records into the Delta table.


https://docs.databricks.com/delta/delta-update.html#upsert-into-a-table-using-merge

https://docs.databricks.com/delta/delta-update.html#insert-only-merge

by Georgiann at May 04, 2025, 11:52 PM

Limited Time Offer

25%

Off

Get Premium Databricks Certified Data Engineer Professional Questions as Interactive Web-Based Practice Test or PDF

Contribute your Thoughts:

Submit Cancel
Ilene
2 days ago
I'm not entirely sure, but I feel like VACUUMing the Delta table is more about cleanup than deduplication, so B seems off.
upvoted 0 times
...
Phung
8 days ago
I remember something about using merge operations to handle duplicates, so I think C might be the right choice.
upvoted 0 times
...
Ligia
13 days ago
Hmm, I'm not sure about this. The options all seem plausible, and I'm not sure I fully understand the nuances of how Delta Lake handles deduplication. I think I'll need to review the Delta Lake documentation again before deciding on an answer.
upvoted 0 times
...
Bernadine
19 days ago
This seems straightforward to me. Option C is clearly the way to go - the insert-only merge will ensure that any duplicate records are skipped, while still allowing new unique records to be added to the Delta table. I feel pretty confident about this one.
upvoted 0 times
...
Kristal
24 days ago
I'm a bit confused by the wording here. What exactly does "deduplicate data against previously processed records" mean? Is that different from just deduplicating within the batch? I'll need to re-read this a few times to make sure I'm understanding it correctly.
upvoted 0 times
...
Tashia
30 days ago
Okay, I think I've got this. The key is to find a way to deduplicate the data as it's being inserted into the Delta table, rather than just within the batch. I'm leaning towards option C - the insert-only merge with a unique key condition.
upvoted 0 times
...
Royal
1 month ago
Hmm, this looks like a tricky one. I'll need to think through the different options carefully to make sure I understand the implications of each approach.
upvoted 0 times
...
Justine
5 months ago
You know, Option A, 'Set the configuration delta.deduplicate = true' sounds a bit too good to be true. I bet there's more to it than just flipping a switch.
upvoted 0 times
...
Sylvia
5 months ago
Ha! Option B, 'VACUUM the Delta table'? That's like trying to sweep dust under the rug. Let's be real, we need a proper deduplication strategy here.
upvoted 0 times
Fallon
3 months ago
That could work, as long as we handle conflicts properly.
upvoted 0 times
...
Tandra
4 months ago
Option D) Perform a full outer join on a unique key and overwrite existing data.
upvoted 0 times
...
Denise
4 months ago
But what if we need to update existing records as well?
upvoted 0 times
...
Natalie
4 months ago
Option C) Perform an insert-only merge with a matching condition on a unique key.
upvoted 0 times
...
...
Maryann
5 months ago
Hmm, I'm not sure about Option E. Relying on Delta Lake schema enforcement alone seems a bit risky for deduplicating data. I'd go with Option C or D.
upvoted 0 times
...
Cristy
5 months ago
I think D) Perform a full outer join on a unique key and overwrite existing data could also be a valid approach.
upvoted 0 times
...
Solange
5 months ago
But wouldn't setting the configuration delta.deduplicate = true also help in deduplicating data?
upvoted 0 times
...
Paris
5 months ago
I think Option D is the way to go. A full outer join on a unique key and overwriting the existing data is a robust way to handle late-arriving, duplicate records.
upvoted 0 times
Ellsworth
4 months ago
Performing a full outer join on a unique key can help prevent any issues with duplicate data in the Delta table.
upvoted 0 times
...
Kenneth
5 months ago
Option D is a good choice. It's important to handle late-arriving, duplicate records effectively.
upvoted 0 times
...
...
Macy
6 months ago
Option C looks like the best approach to me. Performing an insert-only merge with a unique key condition will allow the data engineer to deduplicate the data as it's inserted into the Delta table.
upvoted 0 times
Elly
5 months ago
User 3: It definitely makes sense to prevent duplicate records by merging based on a unique key.
upvoted 0 times
...
Dominga
5 months ago
User 2: Yeah, using a unique key condition in an insert-only merge is a smart approach.
upvoted 0 times
...
Willodean
5 months ago
User 1: I agree, option C seems like the most efficient way to deduplicate the data.
upvoted 0 times
...
...
Lonny
6 months ago
I disagree, I believe the correct answer is E) Rely on Delta Lake schema enforcement to prevent duplicate records.
upvoted 0 times
...
Solange
6 months ago
I think the answer is C) Perform an insert-only merge with a matching condition on a unique key.
upvoted 0 times
...

Save Cancel