Data Warehousing Test Answers 2015



Which of the following implements Multidimensional OLAP?
All of the Above
Microsoft SSAS
Oracle Essbase
IBM TM1


Which of the following is true about Data Scrubbing?
It involves data cleansing
Harmonization of data cannot be considered as Data Scrubbing
It is same as data validation
Standardization of data cannot be considered as Data Scrubbing


When is it appropriate to use a Joiner Transformation during ETL?
When the two sources have a primary-key to foreign-key relationship
When the two sources have multiple matching columns
When the two sources are heterogeneous
All of the Above


Which MDX operation returns all possible combinations of one or more sets?
Leaves
AllMembers
Distinct
Crossjoin


What is an example of an OLAP dice operation?
randomizing the year and region
randomizing the year
specifying a particular year and region
specifying a particular year


Which of the following systems is optimized for multidimensional analysis?
OLTP
OLAP
SQL
ETL


Which system is appropriate for recording customer transactions in real time?
Star Schema
Snowflake Schema
OLAP
OLTP


Which of the following is true about Data Warehousing?
It is designed to facilitate reporting and analysis
All of the given options are true
It is a non-volatile time-variant repository
It is copy of transaction data specifically structured for query and analysis


Which of the following is true about Snowflake schema?
It is represented by centralized fact tables
It is a variation of the star schema
Its a logical arrangement of tables in a multidimensional database
All of the above


What is the process by which raw data is migrated into a data warehouse?
Export, Transmit, Load
Extract, Transform, Load
Export, Translate, Load
Extract Test Language


Which of the following uses the idea of a data cube to represent the dimensions of data ?
OLAP or Multidimensional Database
ODS
Relational Database
OLTP


Data Warehouse (OLAP) is based on which of the following?
Fact Constellation Schema
Star Schema
Snowflake Schema
All of given options are valid


Which of the following are valid Logical Extraction methods?
Online extraction
Full Extraction
Both Full Extraction and Incremental Extraction
Incremental Extraction


Which of the following is TRUE about MOLAP?
Data is stored in a multidimensional cube.
MOLAP cubes are built for fast data retrieval
All of the given options are valid
MOLAP cubes are optimal for slicing and dicing operations


Which of the following is true about Data mining?
All of the given options are valid
It is the process of analyzing data from different perspectives and summarizing it into useful information
It is the process of finding correlations or patterns among various fields
It allows users to analyze data from many different dimensions or angles


Which of the following is VALID about time-variant characteristic of a data warehouse?
Time horizon of a data warehouse is significanlty longer than that of operational systems
All of the given options are valid
Data warehouses contain data that is generally loaded from the operational databases on a regular interval
Data Warehouse maintains both historical and (nearly) current data


Which of the following is TRUE about ROLAP?
All of the given options are valid
Can leverage functionalities inherent in the relational database
Performance can be slow
Can handle large amounts of data


Operational Database(OLTP) is based on which of the following?
Snowflake Schema
Fact Constellation Schema
Star Schema
Entity Relationship Model


What table is at the center of a star schema?
fact table
dimension table
core table
metadata table


What is the "grain" of a fact table?
the raw data from which the facts are derived
the ratio of facts to dimensions
the direction along which additive measures can be combined
the most atomic level at which the facts may be defined


Which of the following is true about Specialized SQL servers?
It uses array-based multidimensional storage engines
It facilitates OLTP operations in SQL
It provides advanced query language and query processing support for SQL queries over star and snowflake schemas
It uses the two level of data storage representation to handle dense and sparse data sets


Which of the following operations navigate data from less detailed data to highly detailed data?
Roll-up
Drill-up
Drill-down
Roll-down


A data warehouse is built as a separate repository of data, different from the operational data of an enterprise because?
A data warehouse cannot afford to allow corrupted data within it
It is necessary to keep the operational data free of any warehouse operations
A data warehouse contains summarized data whereas the operational database contains transactional data
It contains data derived from multiple sources


The ‘Slice’ operation deals with?
Merging the cells of all but one dimension
Selecting the cells of any one dimension of data cube
Merging the cells along one dimension
Selecting all but one dimension of the data cube.


Which of the following is true about 'Pivot' operation?
It rotates the data axes in view in order to provide an alternative presentation of data
All of the given options are valid
It is also known as rotation
Two consecutive slice operations in two different dimensions


Modifying an OLAP Cube to view information from only a single year is an example of which operation?
slice
join
dice
pivot


Where does cleansing take place during the ETL phase of data bound for a MOLAP based data warehouse?
Cleanroom Table
Staging Area
ODS
No distinct cleansing phase, data cleansed during MDX queries


Which language is appropriate for querying a non-relational OLAP database?
MDX
SQL
Fortran
SPSS


Which of the following is a method for delta detection during the ETL process?
audit columns
CRC
(none of these choices)
(both of these choices)


Which of the following is an example of a non-aggregatable measure?
costs
probability of default
transaction volume
gross profits


Which of the following is NOT a benefit of data warehousing?
To integrate data from multiple source systems
To maintain data history
To collate data from multiple sources into a multiple databases
To enhance data quality


Choose the most correct statement:
Star and snowflake schema contains two Fact tables
Fact Constellation schema contains two Fact tables
Snowflake schema contains two Fact tables
Star schema contains two Fact tables


What is a Data Mart?
an access layer comprising a subset of a data warehouse
a schema that organizes data into facts and dimensions
an online, open exchange in which organizations can trade business information
a central repository where separate organizations can securely backup data


Which of the following would not be a part of the fact table of a star schema representing sales data?
Units sold
Store UID when a Store dimension table exists
Product name when a Product dimension table exists
None of the Above


Which line is not a valid MDX comment?
/* this line */
-- this line
## this line
// this line


Which of the following environments has a higher amount of Joins
OLTP
Database
OLAP
Data Warehousing env


Which of the following is not a VALID characteristic of data warehouse?
Integrated
Volatile
Subject Oriented
Nonvolatile


What is an OLAP Cube?
a dimensional-reduction operation that summarizes data
None of the Above
a three-dimensional array for Online Analytical Processing
an array in which data is stored and characterized by multiple dimensions


Which of the following can present summary data from an OLAP server?
normalization
primary keys
pivot tables
All of the Above


Which of the following contains historical data?
OLTP
Both OLAP and OLTP
OLAP
Neither OLAP nor OLTP


Which of the following enviroments are in third normal form 3NF?
OLTP
Data Warehousing env
OLAP
All of the options are correct


Which of the following schema is generally the most denormalized?
Reverse Snowflake
Hub and Spoke
Snowflake
Star


Which of the following operation is performed by introducing new dimensions?
Roll-down
Drill-down
Drill-up
Roll-up


Which of the following is a valid disadvantage of a dimensional approach?
Dimensional structures are difficult to understand for business users
The retrieval of data from the data warehouse tends to become slow
Loading the data warehouse with data from different operational systems is complicated
Data warehouse gets complicated for the user to understand and to use


Which of the following is true about 'Dice' operation?
The Dice operation performs selection of two or more dimension on a given cube
The Dice operation performs selection of one dimension on a given cube
It navigates the data from less detailed data to highly detailed data
It forms a new sub-cube by selecting one or more dimensions


Which of the following is true about multidimensional models?
It uses just one level of data storage representation to handle sparse data sets
It uses just one level of data storage representation to handle dense data sets
It uses two level of data storage representation to handle dense and sparse data sets
It uses one level of data storage representation to handle both dense and sparse data sets


Which operation on a multidimensional database is most equivalent to a relational join?
dice
slice
rotating
drill-across


Choose the most correct statement:
Fact Constellation schema contains denormalized Dimension table
Star schema contains normalized Dimension table
Snowflake schema contains denormalized Dimension table
Snowflake schema contains normalized Dimension table


In which of the data storing approaches does transaction data get partitioned into facts?
dimensional approach
Both dimensional and normalized approach
normalized approach
Neither dimensional nor normalized approach


What Amazon Reshift compression encodings would be most appropriate for the columns (Date, City, Description), respectively?
Delta, Byte-dictionary, LZO
MOSTLY8, Runlength, Raw
LZO, Delta, Raw
Byte-dictionary, LZO, Delta


Which of the following is not a type of OLAP?
Multidimensional
Analytical
Hybrid
Relational


Which of the following is a property of Data Warehouse data?
Write Deconditional
Write Only
Read Only
Read and Write


In a 3-tier architecture of the data warehouse, the OLAP engine is related to:
The fourth layer of the architecture
The Second layer of the architecture
The third layer of the architecture
The first layer of the architecture


In order to populate the data warehouse, which of the following set of operations are appropriate?
Query and update
Create and edit
Refresh and load
Insert and delete


Which of following stages involve data update in the warehouse for every transaction performed on the source data?
On time data warehouse
Offline data warehouse
Offline operational data warehouse
Integrated data warehouse


Which of the following operations performs aggregation on a data cube by dimension reduction?
Drill-down
Roll-up
Drill-up
Roll-down


Which of the following applies to Fact Tables?
Partially normalized
Completely normalized
Completely denormalized
Partially denormalized


‘ROLAP’ is preferred over ‘MOLAP’ in which of the following cases?
A data warehouse and relational database are separable
When fast data retrieval is required
When slicing and dicing is required
When there is a requirement to perform complex calculation


What is the principal disadvantage of Type 3 Slowly Changing Data management?
Updates obsolete data with new values infrequently
Does not track historical data
Stores only a finite number of historical changes
Significantly increases storage requirements per record


An ETL Joiner Transformation is performed on Source A with 10,000 rows and Source B with 25,000 rows. Which source should be the master?
Source B to prevent rows from being omitted
Source A to speed up the join process
None of the Above
There is no master-detail distinction, Joiner Transformations gives both sources parity


Which of the following is the most appropriate data structure for indexing a MOLAP Cube?
Index table
Bitmap index
Huffman encoding
B-Tree


Which of the following is not a property of a perspective?
Can securely restrict access to objects in a cube
Can hide any number of dimensions from a cube
Can display hierarchies from a cube
Can provide business-specific viewpoints of a cube


Among the following, which is NOT the objective of clustering?
To initiate hypothesis about the data
To find consistent and valid organizations of the data
It facilitates OLAP operations
To cover natural groupings


Which of the following is not an advisable implementation of division in MDX?
measures.[Value A]/measures.[Value B]
None of the Above
iff(measures.[Value A]=0, null, measures.[Value A]/measures.[Value B])
Divide(measures.[Value A]/measures.[Value B], null)


When is a column-based engine a more appropriate architecture for a Data Warehouse than a row-based engine?
small number of known indexes to be created, static query patterns
a column-based engine is only appropriate for OLTP applications
most columns in a table will be required for a query
dynamic, unpredictable query patterns


Which of the following is not TRUE about subject oriented characteristics of a data warehouse?
Data warehouse has a defined scope
Data should not change once it is entered into the warehouse
Data is manipulated to provide information about a particular subjec
Data that are never deleted once they have been added


Which of the following is an appropriate method for mitigating the database explosion associated with sparse dimensions?
populate the sparse dimension with filler values
apply Type 6 updating to the sparse dimension
create a composite to stand-in for the sparse dimension
isolate the sparse dimension in a separate cube


What are the following is not a requirement of First Normal Form?
Separate tables for each group of related data with a unique identifier for each row
None of the Above
No duplicate columns within a single table
No columns that are not dependent on a primary key


Which of the following is not a valid context for the MDX From clause?
a perspective (subset of measures and dimensions
a subcube (nested MDX query)
None of the Above
a cube


Which of the following environments has more indexes?
OLAP
Data Warehousing env
OLTP
Database


What is true of querying normalized data in a relational database for the purposes of business analysis?
Aggregating relevant data requires the creation of new primary keys
The data must first be placed into a data warehouse via the ETL process
Aggregating relevant data requires multiple table joins
All of the Above


What is a slice in the context of Amazon Redshift?
A logical partition of the data layer shared between distributed compute nodes
A parallel operation isolating a single layer of a Redshift cube
A client-facing partition that isolates different parts of the data warehouse for different types of users in an organization
A partition allowing each of core of a multi-processor node to process the node's workload in parallel


Choose the most correct statement:
OLAP is more flexible then OLTP
Data mining and data warehousing are totally unrelated
Data mining and data warehousing are the same
Data warehousing is the application of data mining


Without deliberate security measures, which of the following MDX clauses is susceptible to injection attack?
WHERE
All of the Above
WITH
FROM


Which of the following is a required property of information passed to the Microsoft Sequence Clustering Algorithm?
normalized data with key sequence columns on each dimension table
sequence information stored as a nested table
star schema with key sequence columns on each dimension table
sequence information stored as a flat table


What property do Router Transformations and Filter Transformations have in common?
All of the Above
single input group transformation
single output group transformation
will not block input rows


Where is the OLAP page pool stored in memory in an Oracle Database 10g and later?
Private SQL Area
SQL Work Area
User Global Area
Program Global Area


Online extraction process falls under which type of data extraction method?
Incremental Extraction
Physical Extraction
Logical Extraction
Full Extraction


A data warehouse is an ‘integrated’ collection of data because?
It is a collection of data of derived from multiple sources
It contains summarized data
It is a collection of data of different types
It is a relational database


All else being equal, which of the following elements of a single MDX WHERE clause will evaluate first?
MEMBER [Measures].[C Less One] AS [Measures].[Measure C] - 1, SOLVE_ORDER = 1
All elements evaluate simultaneously
MEMBER [Measures].[B Twice] AS [Measures].[Measure B] + [Measures].[Measure B], SOLVE_ORDER = 4
MEMBER [Measures].[A Squared] AS [Measures].[Measure A] * [Measures].[Measure A], SOLVE_ORDER = 2

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