Get Unlimited Contributor Access to the all ExamTopics Exams!
Take advantage of PDF Files for 1000+ Exams along with community discussions and pass IT Certification Exams Easily.
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.
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.
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.
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.
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
A voting comment increases the vote count for the chosen answer by one.
Upvoting a comment with a selected answer will also increase the vote count towards that answer by one.
So if you see a comment that you already agree with, you can upvote it instead of posting a new comment.
asmayassineg
Highly Voted 4 months, 1 week agoaragorn_brego
Most Recent 2 weeks, 6 days agoBIKRAM063
1 month, 1 week agosturcu
2 months agoSantitoxic
2 months, 2 weeks agoNaveenkm
2 weeks agoStarvosxant
2 months agolucasasterio
3 months agorobson90
3 months, 2 weeks agorobson90
3 months, 2 weeks agoBrianNguyen95
3 months, 3 weeks ago