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Data Warehouse - Foundations 2

Total questions: 18

Worksheet time: 29mins

Name
Class
Date
1.

Data mining means______

a)

data fetching

b)

data accesing

c)

knowledge discovery

2.
In data warehousing what is time-variant data?
a)
Data in the warehouse is only accurate and valid at some point in time or over time interval
b)
Data in the warehouse is always accurate and valid 
c)
Data in the warehouse is not accurate
d)
Data in the warehouse is only accurate sometimes
3.

Is the data in a data warehouse generally updated in real-time?

a)

Yes

b)

No

4.
What does OLTP stand for?
a)
Online transaction processing
b)
Offline transaction processing
c)
Outline trajectory processing
d)
Online traffic processing
5.
What is a Star Schema?
a)
A star schema consists of a fact table with a single table for each dimension
b)
A star schema is a type of database system
c)
A star schema is used when exporting data from the database
d)
None of these
6.
What is a Snowflake Schema?
a)
Each dimension table is normalized, which may create additional tables attached to the dimension tables
b)
A Snowflake schema is a type of database system
c)
A Snowflake schema is used when exporting data from the database
d)
None of these
7.

What does the acronym ETL stands for?

a)

Explain,Transfer and Lead

b)

Extract,Transform and Load

c)

Extract,Transfer and Load

d)

Effect,Transfer and Load

8.

What is the system of data warehousing mostly used for?

a)

Data integration and Data Mining

b)

Data Mining and Data Storage

c)

Reporting and Data Analysis

d)

Data Cleaning and Data Storage

9.

Which small logical units do data warehouses hold large amounts of information?

a)

Data Storage

b)

Data Marts

c)

Access Layers

d)

Data Miners

10.

Why data analysis is needed? (select all that apply)

a)

require tactical and strategic decisions

b)

business environment is dynamic

c)

search for competitive advantage

d)

to get more public attention

11.

The main characteristics of online analytical processing:

a)

Use single dimension data analysis techniques

b)

Provide advanced database support (drill-down/roll-up)

c)

Provide low level user interface

d)

Do not support client/server architecture

12.

Why do we need ODS? You may answer multiple correct answers

a)

To isolate from production

b)

To update data periodically

c)

To prepare data for ETL

d)

To back up data

13.

Which one is correct for data warehousing?

a)

It can be updated by end users

b)

It can solve all business questions

c)

It is designed for focus subject areas

d)

It contains only current data

14.

Which one come first to build data warehouse

a)

Data Cleansing

b)

Business questions

c)

Data Acquisition

d)

Data Profiling

15.

Why do we apply snowflake schema?

a)

Aggregation

b)

Normalization

c)

Generalization

d)

Transformation

16.

What is WRONG about surrogate key?

a)

It is a list of running numbers

b)

It is a primary key of fact table

c)

It is designed for handling slowly change dimension problem

d)

It is the join key between fact and dimension table

17.

What is CORRECT about data warehouse? You may answer more than one

a)

It makes use of historical data to answer business questions

b)

It reveals insight from data

c)

It supports roll-up and drill-down to explore data

d)

Its design is the same as database

18.

What is the relationship type between fact and dimension table in star schema?

a)

Many-to-Many

b)

One-to-One

c)

One-to-Many

d)

Many-to-One