WorksheetsPretest Data Warehouse Modelling
Total questions: 25
Worksheet time: 13mins
The term Data Warehouse was coined by Bill Inmon in 1990, which
he defined in the following way:
"A warehouse is a subject-oriented, integrated, stable and volatile collection of data in support of management's decision making process".
"A warehouse is a subject-oriented,integrated, time-variant and non-volatile collection of data in support of management's decision making process".
Both A and B
None of above
Which is difficult topic in this unit?
OLAP SERVER
DATA WAREHOUSING ARCHITECTURE
STAR SCHEMA
FACT CONSTELLATION
Definition of Subject Oriented Data: Data that gives information about a particular subject
instead of about a company's ongoing operations.
True
False
Definition of Integrated Data: Data that is gathered into the data warehouse from a variety of sources and merged into a coherent whole.
True
False
Your opinion about use of ROLAP and MOLAP.
Benefits of Data warehousing are:
1. Data warehouses are designed to perform well with aggregate queries running on large amounts of data.
2. The structure of data warehouses is easier for end users to navigate, understand and query against unlike the relational databases primarily designed to handle lots of transactions.
3. Data warehouses enable queries that cut across different segments of a company's operation. E.g. production data could be compared against inventory data even if they were originally stored in different databases with different structures.
4. Queries that would be complex in very normalized databases could be easier to build and maintain in data warehouses, decreasing the workload on transaction systems.
5. Data warehousing is an efficient way to manage and report on data that is from a variety of sources, non uniform and scattered throughout a company.
6. Data warehousing is an efficient way to manage demand for lots of information from lots of users.
1,2,4,6
1,3,2,5
1,2,3,4
1,2,3,4,5,6
Select easiest topic in this unit
OLTP vs OLAP
OLAP servers
Architecture
Schemas
Operational Data is:
Focusing on transactional function such as bank card withdrawals and deposits
Detailed
Updateable and Reflects current data
All of above
Explain Data mart with example
Informational Data is:
Focusing on providing answers to problems posed by decision makers
Summarized
Non updateable
All of above
Hive created by
Amazon
Yahoo!
Hive is a
Data Warehousing Tool
DataBase Management Tool
Data Scrapping Tool
Hadoop Data Tool
Hive don't make use of following:
HDFS for Storage
MapReduce for Execution
Stores metadata in a RDBMS
GPU for Processing
HQL is ______________ to SQL
Similar
Dissimilar
Hive __________ SQL queries _________ MapReduce Jobs
create, convert into
compiles, into
execute, from
interpret, of
Which of them is not hive feature?
easy to code
support rich datatypes
supports group-by
UDF not supported
A database is namespace for
tables
fields
records
keys
Separation of data on basis of specific attribute is
Partition
Bucketting
Fragmentation
Slicing
Separation of data on basis of mathematical hash function is
Partition
Bucketting
Fragmentation
Slicing
What is the right visual charter of HIVE Application?
What hive is not
online transaction processing
Data Warehousing tool
Similar to SQL
Analyze log data
Hive is suitable for
real-time queries
row-level updates
queries over small data sets
analyze historical data
Applications of Apache Hive
Log processing
OLTP
Billing systems
Processing Web Forms
Hive enables easy data summarization, ad-hoc querying and analysis of large volumes of data.
true
false
In _________ due to equal volumes of data in each partition, joins at Map side will be quicker.
bucketing
partitioning
