Lecture 2: SQL and Data Warehousing

Question 1

What is cardinality?

Answer 1

The way tables are related.

Question 2

Which three types of cardinality are there?

Answer 2

One-to-one
One-to-many
Many-to-many

Question 3

What is a Data Warehouse?

Answer 3

A database that is maintained separatly from operational databases for the purpose of decision-making.

A collection of data that support decision-making processes.

Question 4

Why is there a need of a seperate Data Warehouse?

Answer 4

1. Data quality
2. Historical data.
3. Data consolidation

Question 5

Which components does a Datawarehouse architecture consist of?

Answer 5

1. Production
2. ETL
3. Data Warehouse
4. Data Marts
5. Metadata
6. BI applications

Question 6

What is a Datawarehouse?

Answer 6

1. Subject orientated (focus on analysis)
2. Integrated (integrating multiple sources)
3. Time-variant (longer history/time horizon)
4. Non-volatile (no operational updates)

Question 7

Which 7 architecture Datwarehouse types are there?

Answer 7

1. Canned Data Warehouse (within SAP).
2. Independent Data Marts (Multiple Data Marts).
3. Bus architecture (interconnected Data Marts).
4. Enterprise Data Warehouse (Single DWH).
5. Hub & Spoke (DWH and Data Marts).
6. Federated Data Warehouse (DWH and Data Marts both directly connected to source database).
7. Data Lake (Unstructered storage)

Question 8

What is an DSS?

Answer 8

Decision Support System, a set of expandable IT techniques for processing adn analyzing data.

Question 9

What is ETL?

Answer 9

Extract
Transform
Load

Question 10

What is multi-dimensional modeling?

Answer 10

Looks at the measures and dimensions of values of a “fact”. and is the basis for OLAP cube.

Question 11

Meta-data can be classified into?

Answer 11

Internal and external meta-data.

Question 12

Which comes after the Data Warehouse?

Answer 12

Reporting
Dashboards
OLAP