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Exam Certified Data Engineer Professional topic 1 question 28 discussion

Actual exam question from Databricks's Certified Data Engineer Professional

Question #: 28
Topic #: 1

[All Certified Data Engineer Professional Questions]

A junior data engineer seeks to leverage Delta Lake's Change Data Feed functionality to create a Type 1 table representing all of the values that have ever been valid for all rows in a bronze table created with the property delta.enableChangeDataFeed = true. They plan to execute the following code as a daily job:

Which statement describes the execution and results of running the above query multiple times?

A. Each time the job is executed, newly updated records will be merged into the target table, overwriting previous values with the same primary keys.
B. Each time the job is executed, the entire available history of inserted or updated records will be appended to the target table, resulting in many duplicate entries.
C. Each time the job is executed, the target table will be overwritten using the entire history of inserted or updated records, giving the desired result.
D. Each time the job is executed, the differences between the original and current versions are calculated; this may result in duplicate entries for some records.
E. Each time the job is executed, only those records that have been inserted or updated since the last execution will be appended to the target table, giving the desired result.

Show Suggested Answer

Suggested Answer: B 🗳️

by asmayassineg at Aug. 2, 2023, 12:40 p.m.

Comments

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KadELbied

1 month, 1 week ago

Selected Answer: B

select B

upvoted 1 times

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Chugs

3 months, 2 weeks ago

Selected Answer: B

As update type is insert and update so B is correct option.

upvoted 1 times

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asdsadasdas

4 months ago

Selected Answer: B

B, Spark.read reads the entire table every time processed. If it was readstream then E would be answer

upvoted 3 times

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Ashish7singh2020

4 months, 2 weeks ago

Selected Answer: B

since start version is 0

upvoted 1 times

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akashdesarda

7 months, 2 weeks ago

Selected Answer: B

The starting version is 0, that means in every version entire data will be fetched. It is then append.

upvoted 1 times

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faraaz132

10 months, 2 weeks ago

Correct Answer: B (not E) Although it was pretty obvious to me, I still wrote the code to check and yes, it will append the entire change during every write since starting version is mentioned as 0. If in doubt, code it yourselves

upvoted 2 times

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imatheushenrique

1 year ago

("startingVersion", 0) that means the entiry history of table will be read so B.

upvoted 3 times

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PrashantTiwari

1 year, 4 months ago

B is correct

upvoted 2 times

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kz_data

1 year, 5 months ago

Selected Answer: B

B is correct

upvoted 2 times

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5ffcd04

1 year, 5 months ago

Selected Answer: B

Correct B

upvoted 1 times

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azurelearn2020

1 year, 6 months ago

Selected Answer: B

correct answer is B.

upvoted 1 times

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[Removed]

1 year, 6 months ago

Selected Answer: E

Considering that we are talking about Change Data Feed and the code is filtering by[ "update_postimage", "insert" ] the column "_change_type", I would go with the option E. Reference: https://docs.delta.io/latest/delta-change-data-feed.html#:~:text=_change_type,update_preimage%20%2C%20update_postimage

upvoted 1 times

5ffcd04

1 year, 5 months ago

Notice option ("startingVersion", 0), which will bring all changes from begining. Hence Answer is B.

upvoted 6 times

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jyothsna12496

1 year, 8 months ago

why is it Not E. It gets newly inserted or updated records

upvoted 1 times

[Removed]

1 year, 6 months ago

I'm with you, follow the reference: https://docs.delta.io/latest/delta-change-data-feed.html#:~:text=_change_type,update_preimage%20%2C%20update_postimage

upvoted 1 times

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