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WorksheetsUNIT-1 Data Warehousing and OLAP (A sec)
Total questions: 50
Worksheet time: 50mins
What is the key purpose of a data warehouse?
Handle daily transactions
Manage passwords
Real-time processing
Support decision-making
Who defined a data warehouse as “subject-oriented, integrated, time-variant, and nonvolatile”?
Ralph Kimball
Bill Gates
Larry Ellison
W.H. Inmon
Which of the following best describes the "subject-oriented" nature of data warehouses?
Real-time updates
Transaction-level focus
Organized by file type
Focused on major business subjects like sales and customers
Data warehouses integrate data from:
Only XML files
Only spreadsheets
One homogeneous source
Multiple heterogeneous sources
Which property of data warehouse indicates that it retains historical data?
Subject-oriented
Integrated
Nonvolatile
Time-variant
What does "nonvolatile" mean in the context of data warehouses?
Data changes frequently
Data is volatile
Data is deleted periodically
Data is not updated in real time
Which of the following is NOT an advantage of using a data warehouse?
Improved query performance
Separation from operational systems
Real-time transactional updates
Historical trend analysis
Operational databases are optimized for:
Analytics
Visualization
Aggregation
Transactions
A system designed to help executives analyze business performance is likely using:
OLTP
Email server
ERP
OLAP
Which of the following supports real-time transaction processing?
OLAP
Data marts
Data cubes
OLTP
Which data warehouse model provides a virtual view without storing data physically?
Data Mart
Enterprise Warehouse
OLTP
Virtual Warehouse
The bottom tier of data warehouse architecture is responsible for:
Displaying reports
OLAP operations
User input
Data storage and extraction
The middle tier of data warehouse architecture is typically:
Reporting tool
Metadata storage
Query language
OLAP server
ROLAP stands for:
Real-time OLAP
Rapid OLAP
Relational OLAP
Reporting OLAP
MOLAP stands for:
Modular OLAP
Mobile OLAP
Multidimensional OLAP
Managed OLAP
In HOLAP, the advantages of which OLAP types are combined?
SOLAP and COLAP
ROLAP and MOLAP
MOLAP and IOLAP
WOLAP and DOLAP
What is the role of the top tier in a data warehouse?
Load data
Perform extraction
Store data
Provide query and reporting tools
In ETL, the "T" stands for:
Transfer
Transport
Terminate
Transform
Data cleaning is typically part of which ETL phase?
Load
Extract
Analyze
Transform
Which of the following is a correct ETL order?
Transform – Extract – Load
Load – Extract – Transform
Extract – Transform – Load
Extract – Load – Transform
A metadata repository stores:
Reports
Only user credentials
Data files
Information about warehouse structure and content
What is the function of the fact table?
Store only dimension data
Contain metadata
Store measures and foreign keys
Hold index values
Which schema contains a centralized fact table and several denormalized dimension tables?
Snowflake
Fact constellation
Hierarchical
Star
Which schema is a normalized version of the star schema?
Hierarchical
Circular
Linear
Snowflake
A galaxy schema is also known as:
Star schema
OLTP model
Loop schema
Fact constellation
A dimension table is used to:
Perform transactions
Create indexes
Categorize facts and measures
Store error logs
In a data cube, what does each axis represent?
Database name
Server location
Dimensions
Primary keys
What is the top-most cuboid in a lattice of cuboids?
Mid-level cuboid
Root cuboid
Summary cuboid
Apex cuboid
Which OLAP operation involves moving from summary data to detailed data?
Slice
Pivot
Roll-up
Drill-down
Which OLAP operation summarizes data by reducing dimensions?
Drill-down
Slice
Pivot
Roll-up
Selecting a single dimension from the cube is known as:
Pivot
Drill-across
Dice
Slice
What operation rotates the cube to provide a different data view?
Roll-up
Drill-down
Slice
Pivot
In OLAP, what is a “drill-through”?
Rotate the view
View the raw data from the lowest level
Summarize high-level data
Create new dimensions
Which OLAP server is ideal for very large data volumes stored in relational databases?
HOLAP
MOLAP
WOLAP
ROLAP
What type of OLAP server uses pre-computed cubes for fast querying?
ROLAP
COLAP
DOLAP
MOLAP
What is a major advantage of HOLAP?
Works only with flat files
Slow computation
Combines ROLAP and MOLAP benefits
Minimal memory usage
The data cube measure type “distributive” includes:
avg()
median()
mode()
sum()
Which measure type can be computed using distributive functions?
Holistic
Relational
Algebraic
Conceptual
Which of the following is a holistic measure?
count()
sum()
avg()
median()
Which OLAP server provides quick access at all aggregation levels?
SOLAP
MOLAP
ROLAP
HOLAP
What kind of data is supported by OLAP servers?
Raw logs
Multidimensional data
Single flat table
Temporary files
Which schema supports shared dimension tables for multiple fact tables?
Snowflake
OLTP
Star
Fact constellation
What is the primary design model of data warehouses for business users?
ER model
Relational model
Transactional model
Dimensional model
A cube operation that selects multiple dimensions with specific values is called:
Drill-down
Slice
Pivot
Dice
Which component stores business terms, ownership, and policies in metadata?
Index table
Audit log
OLTP log
Business metadata
The concept hierarchy in a dimension helps in:
Encrypting data
Indexing queries
Rolling up or drilling down data
Creating star schemas
Which type of schema is easiest to maintain?
Star
Fact constellation
OLTP
Snowflake
What is the first step in building a data warehouse using the recommended approach?
Create dimension tables
Build fact tables
Generate queries
Define a high-level corporate data model
What is a data mart?
Temporary storage
Real-time system
Operational data subset
Department-specific subset of data warehouse
What is the purpose of using OLAP technology in business intelligence?
Automate emails
Perform transactions
Visualize and analyze multidimensional data
Send notifications
