May 06, 2018

Data Warehouse - MCQS


Question.
The data Warehouse is______.
A. read write only.
B. write only.
C. read only.
D. none.
ANSWER: A

Question.
__________ is a subject-oriented, integrated, time-variant, nonvolatile collection of data in support of
management decisions.
A. Web Mining.
B. Data Warehousing.
C. Data Mining.
D. Text Mining.

ANSWER: B

Question.
If you have to summarize data as per hierarchy in dimension attributes, which is appropriate SQL clause?

Select one:
SUM
HAVING
WHERE
ROLLUP

Answer: ROLLUP

Question.
Which of the following is Apache data warehouse?

Select one:
Hbase
Sqoop
HDFS
Hive

Answer: Hive

Question.
A Data Mart whose source is directly from transactional systems, legacy applications, or external data feeds

Select one:
Dependent Data Mart
Intra-entry Data Mart
Independent Data Mart
Inter-entry Data Mart

Answer: Independent Data Mart

Question.
The difference between ROLLUP and CUBE in SQL is

Select one:
CUBE summarizes for all combinations while ROLLUP does along hierarchy
CUBE summarizes along a hierarchy while ROLLUP does for all combinations
CUBE and ROLLUP handle NULLs differently
CUBE and ROLLUP are the same

Answer: CUBE summarizes for all combinations while ROLLUP does along hierarchy

Question.
Data scrubbing is which of the following?

Select one:
A process to load the data in the data warehouse and to create the necessary indexes
A process to upgrade the quality of data before it is moved into a data warehouse
A process to aggregate data after it is moved into a data warehouse
A process to reject data from the data warehouse and to create the necessary indexes


Answer: A process to upgrade the quality of data before it is moved into a data warehouse

Question.
Which of the following is NOT a kind of data warehouse application?

Select one:
Data mining
Analytical processing
Information processing
Transaction processing

AnswerTransaction processing

Question.
Which one of the following is NOT a characteristic of metadata?

Select one:
Self-describing
Includes user data
Data about data
Helps user to build ad-hoc queries

Answer: Includes user data

Question.
A _______ is a table on disk that contains the result set of a query

Select one:
Materialized View
Pivot
View
Table

AnswerMaterialized View

Question.
Which one is NOT the Codd’s rule for OLAP?

Select one:
Restricted cross dimensional operation
Transparency
Consistent Reporting Performance
Intuitive Data Manipulation

Answer: Restricted cross dimensional operation

Question.
A bitmap index is most appropriate on which of these columns

Select one:
Salary
Gender
Date of Birth
Name

Answer: Gender

Question.
SQL Windowing is based on

Select one:
Partitions defined for the table
Indexes
Materialized Views
Partitions defined in query

Answer: Partitions defined in query

Question.
The SQL analytical function to divide records into equal sized groups is

Select one:
PERCENTILE
GROUP BY
NTILE
QUARTILE

Answer: NTILE

Question.
The operation of moving from coarser granularity data to a finer granularity  is called

Select one:
Drill down
Dice
Rollup
Slice


AnswerDrill down

Question.
Views in SQL are of the type

Select one:
Always Physical
Sometimes physical
Always Virtual
Always up-to-date

AnswerSometimes physical

Question.
MOLAP stores aggregate values in which of the following structure?

Select one:
Table
Index
View
Array

AnswerArray

Question.
Which of the following OLAP techniques offers best latency?

Select one:
ROLAP
MOLAP
DOLAP
HOLAP

Answer: ROLAP

Question.
Aggregate navigator is based on

Select one:
Indexes
Summary tables
Logical Views
Materialized Views

AnswerMaterialized Views

Question.
Summarization for a table is to be done using 4 attributes. How many SQL statements using GROUP BY are required to produce equivalent results?

Select one:
4
8
64
16

Answer: 16

Question.
Difference between Rank and Sort in SQL is

Select one:
Sort allows aggregates while Rank does not
Rank gives a separate sequence of numbers
Sort is based on attribute while Rank is not
They are same

AnswerRank gives a separate sequence of numbers

Question.
Dimensions D1 and D2 are not considered conforming if

Select one:
D1 columns are subset of D2
D1 identical to D2
D1 and D2 are present on the same server
D1 is rolled up subset of D2

AnswerD1 and D2 are present on the same server

Question.
In SQL, what is the difference between GROUP BY and PARTITION BY clauses ?

Select one:
They are same.
SELECT clause
Type of attributes
WHERE clause

AnswerWHERE clause

Question.
When were analytic functions introduced in SQL?

Select one:
2011
1999
1992
2003


Answer2003

Question.
What is the difference between Rank and Dense_Rank in SQL?

Select one:
Rank and Dense_Rank are the same
Dense_Rank uses consecutive numbers
Dense_Rank hides some results
Dense_Rank rejects duplicates


Answer: Dense_Rank uses consecutive numbers

Question.
The type of relationship in star schema from dimension to fact is

Select one:
Many-to-Many
One-to-Many
One-to-One
Many-to-one 


Answer: one-to-many 

Question.
A table can not be partitioned by

Select one:
Hash
List
Range

Rank

AnswerRank