Databricks Certified Data Engineer Quiz part 2

A data engineer has realized that the data files associated with a Delta table are incredibly small. They want to compact the small files to form larger files to improve performance. Which of the following keywords can be used to compact the small files?

• REDUCE

• OPTIMIZE

• COMPACTION

• REPARTITION

• VACUUM

In which of the following file formats is data from Delta Lake tables primarily stored?

• Delta

• CSV

• Parquet

• JSON

• A proprietary, optimized format specific to Databricks

Which of the following is stored in the Databricks customer's cloud account?

• Databricks web application

• Cluster management metadata

• Repos

• Data

• Notebooks

Which of the following can be used to simplify and unify siloed data architectures that are specialized for specific use cases?

• None of these

• Data lake

• Data warehouse

• All of these

• Data lakehouse

A data architect has determined that a table of the following format is necessary: Which of the following code blocks uses SQL DDL commands to create an empty Delta table in the above format regardless of whether a table already exists with this name?

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A data engineer has a Python notebook in Databricks, but they need to use SQL to accomplish a specific task within a cell. They still want all of the other cells to use Python without making any changes to those cells. Which of the following describes how the data engineer can use SQL within a cell of their Python notebook?

• It is not possible to use SQL in a Python notebook

• They can attach the cell to a SQL endpoint rather than a Databricks cluster

• They can simply write SQL syntax in the cell

• They can add %sql to the first line of the cell

• They can change the default language of the notebook to SQL

Which of the following SQL keywords can be used to convert a table from a long format to a wide format?

• TRANSFORM

• PIVOT

• SUM

• CONVERT

• WHERE

Which of the following describes a benefit of creating an external table from Parquet rather than CSV when using a CREATE TABLE AS SELECT statement?

• Parquet files can be partitioned

• CREATE TABLE AS SELECT statements cannot be used on files

• Parquet files have a well-defined schema

• Parquet files have the ability to be optimized

• Parquet files will become Delta tables

A data engineer wants to create a relational object by pulling data from two tables. The relational object does not need to be used by other data engineers in other sessions. In order to save on storage costs, the data engineer wants to avoid copying and storing physical data. Which of the following relational objects should the data engineer create?

• Spark SQL Table

• View

• Database

• Temporary view

• Delta Table

A data analyst has developed a query that runs against Delta table. They want help from the data engineering team to implement a series of tests to ensure the data returned by the query is clean. However, the data engineering team uses Python for its tests rather than SQL. Which of the following operations could the data engineering team use to run the query and operate with the results in PySpark?

• SELECT * FROM sales

• spark.delta.table

• spark.sql

• There is no way to share data between PySpark and SQL.

• spark.table