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Exam Certified Data Engineer Professional topic 1 question 16 discussion

Actual exam question from Databricks's Certified Data Engineer Professional
Question #: 16
Topic #: 1
[All Certified Data Engineer Professional Questions]

A table is registered with the following code:

Both users and orders are Delta Lake tables. Which statement describes the results of querying recent_orders?

  • A. All logic will execute at query time and return the result of joining the valid versions of the source tables at the time the query finishes.
  • B. All logic will execute when the table is defined and store the result of joining tables to the DBFS; this stored data will be returned when the table is queried.
  • C. Results will be computed and cached when the table is defined; these cached results will incrementally update as new records are inserted into source tables.
  • D. All logic will execute at query time and return the result of joining the valid versions of the source tables at the time the query began.
  • E. The versions of each source table will be stored in the table transaction log; query results will be saved to DBFS with each query.
Show Suggested Answer Hide Answer
Suggested Answer: D ūüó≥ÔłŹ

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asmayassineg
Highly Voted 4 months, 1 week ago
Correct answer is B. table is created and data of join will be stored on DBFS and it will be returned on query time
upvoted 7 times
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aragorn_brego
Most Recent 2 weeks, 6 days ago
Selected Answer: B
The correct answer is: B. All logic will execute when the table is defined and store the result of joining tables to the DBFS; this stored data will be returned when the table is queried. When the CREATE TABLE AS statement is executed, it runs the enclosed SELECT statement immediately to pull the current data from the users and orders tables where the order_date is within the last 7 days. This result is then stored as a new table called recent_orders in the Delta Lake on the DBFS (Databricks File System). Subsequent queries against recent_orders will return this stored data, and not recompute the join unless the table is updated or refreshed.
upvoted 1 times
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BIKRAM063
1 month, 1 week ago
Selected Answer: B
Correct is B . CTAS command
upvoted 2 times
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sturcu
2 months ago
Selected Answer: B
Creating a table will not display results. You need to make a select alter it is created.
upvoted 1 times
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Santitoxic
2 months, 2 weeks ago
Based on typical Delta Lake behavior, option D is the most accurate description. Delta Lake queries generally execute at query time and retur n results based on the state of the source tables at the time the query began. Delta Lake provides features for managing data versions and transactions, but it doesn't precompute and store results like option B or cache results like option C.
upvoted 1 times
Naveenkm
2 weeks ago
Its create separate delta lake transaction logs for this new table. So B is the correct the answer.
upvoted 1 times
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Starvosxant
2 months ago
No. Simple no. When you execute a create table even with a Join you DONT see the results imediatly unless you query the table. So correct answer is B. The create table statement by default creates a Managed table, which is stored in DBFS.
upvoted 1 times
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lucasasterio
3 months ago
Selected Answer: B
correct is B
upvoted 2 times
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robson90
3 months, 2 weeks ago
Aa ok, I missed "logic will execute at query time" ignore my previous comment
upvoted 1 times
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robson90
3 months, 2 weeks ago
Why not D? Table does not need to be stored on DBFS if using Unity Catalog. At least that's my understanding https://docs.databricks.com/en/dbfs/unity-catalog.html
upvoted 1 times
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BrianNguyen95
3 months, 3 weeks ago
correct answer is B
upvoted 4 times
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A (35%)
C (25%)
B (20%)
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