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.
In a star schema, the number of rows in a dimension table is

Select one:
1. Larger than the fact table
2. Smaller than the fact table
3. Same as in the fact table

4. None of the options

Answer: Smaller than the fact table

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

Answer: Transaction 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

Answer: Materialized 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


Answer: Drill down

Question.
Views in SQL are of the type

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

Answer: Sometimes physical

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

Select one:
Table
Index
View
Array

Answer: Array

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

Answer: Materialized 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

Answer: Rank 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

Answer: D1 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

Answer: WHERE clause

Question.
When were analytic functions introduced in SQL?

Select one:
2011
1999
1992
2003


Answer: 2003

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

Answer: Rank

Question.
A snowflake schema is which of the following type of table?

Select one:
1. Fact
2. Normalized Dimension
3. Factless Dimension
4. All of the above

Answer: All of the above

Question
Enterprise Data Warehouse is a _________________warehouse.

Select one:
1. Public
2. Non Centralized
3. Centralized
4. Private

Answer: Centralized

Question
Which of the following is not a data component of a data warehouse?

Select one:
1. Component Key.
2. Metadata
3. Current detail data.

4. Lightly summarized data.

Answer: Component Key

Question
Data warehouses commonly use a _______________key to uniquely identify an entity for various purposes.

Select one:
1. Composite
2. Primary
3. Super
4. Surrogate

Answer: Surrogate