Certified Data Engineer Professional Exam

Exam Certified Data Engineer Professional All QuestionsBrowse all questions from this exam

Question 39

Which of the following is true of Delta Lake and the Lakehouse?

Because Parquet compresses data row by row. strings will only be compressed when a character is repeated multiple times.

Delta Lake automatically collects statistics on the first 32 columns of each table which are leveraged in data skipping based on query filters.

Views in the Lakehouse maintain a valid cache of the most recent versions of source tables at all times.

Primary and foreign key constraints can be leveraged to ensure duplicate values are never entered into a dimension table.

Z-order can only be applied to numeric values stored in Delta Lake tables.

Correct Answer: B

Delta Lake automatically collects statistics on the first 32 columns of each table which are leveraged in data skipping based on query filters. This helps to optimize query performance by allowing the system to quickly determine which parts of the dataset do not need to be read based on the query conditions.

Discussion

guillesdOption: B

B is correct

PatitoOption: B

B is correct since statistics are collected for the first 32 columns and stored in the transaction log.

PrashantTiwariOption: B

B is correct

spaceexplorerOption: B

B is correct

Crocjun

Can anyone explain why D is not correct?

cryptoflam

Because Primary & Foreign Key information is not enforced. "Primary and foreign keys are informational only and are not enforced" from: https://docs.databricks.com/en/tables/constraints.html#declare-primary-key-and-foreign-key-relationships

ervinshangOption: B

B is correct， C is error, con't have new cache in view

f728f7fOption: C

C is correct

chokthewaOption: B

B is correct. https://docs.delta.io/2.0.0/table-properties.html