Use Delta Lake's Time Travel to Access and Query Historical Data Versions. DATA-ANALYST-ASSOCIATE Practice Questions (Page 5)

Questions 21–22

1. 21application · medium

   A data analyst needs to explain to a colleague why they can query historical versions of a Delta table. The colleague is unfamiliar with Delta Lake. Which explanation is accurate?

   • ADelta Lake stores a full copy of the table for every version, which is why time travel is possible.
   • BDelta Lake automatically backs up all versions to a separate storage location for time travel.
   • CDelta Lake stores all historical data files and metadata, allowing queries to access any previous version.
   • DDelta Lake only keeps the most recent version of the data, but the transaction log allows reconstructing older versions.
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2. 22application · medium

   A data analyst created a view `v_high_value_orders` that filters the `orders` table for orders above $1,000. The analyst needs to query this view as it appeared yesterday. Which statement is correct?

   • AThe analyst can use `SELECT * FROM v_high_value_orders VERSION AS OF 3` to query the view's historical state.
   • BThe analyst should recreate the view with a WHERE clause that filters by a timestamp column.
   • CTime travel cannot be applied directly to a view; the analyst must query the underlying table with time travel.
   • DThe analyst can use `SELECT * FROM v_high_value_orders TIMESTAMP AS OF '2024-03-01'` to query the view's historical state.
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