Data Warehouse Design - Chapter 1.9

Question 1

What are three additional issues with data warehouse design?

Answer 1

1. Quality
2. Security
3. Evolution

Question 2

What are 7 properties that characterize quality?

Answer 2

1. Accuracy
2. Freshness
3. Completeness
4. Consistency
5. Availability
6. Traceability
7. Clearness

Question 3

What is meant by accuracy?

Answer 3

Stored values should be compliant with real-world ones.

Question 4

What is meant by freshness?

Answer 4

Data should not be old.

Question 5

What is meant by completeness?

Answer 5

There should be no lack of information.

Question 6

What is meant by consistency?

Answer 6

Data representation should be uniform.

Question 7

What is meant by availability?

Answer 7

Uses should have easy access to data.

Question 8

What is meant by clearness?

Answer 8

Data can be easily understood.

Question 9

What is an example metric for accuracy and completeness?

Answer 9

The percentage of tuples not loaded by an ETL prcess and categorized on the basis of the types of problem arising.
-> shows percentage of missing, invalid and nonstandard values of every attribute.

Question 10

What is an example metric for freshness?

Answer 10

Time elapsed between the date when an event takes place and the date when users can access it.

Question 11

What is an example metric for consistency?

Answer 11

Percentage of tuples that meet business rules that can be set for measures of an indvidual cube or many cubes.

Question 12

How can database designers try to improve data quality in a firm?

Answer 12

1. Get senior management involved to define a certification system that defines a limited group of users in charge of data.
2. Standardizing documentation to ensure that different data warehouse project phases are correctly carried out and that all analysis and implementation points are properly examined and understood.

Question 13

For which 3 reasons is security particularly relevant to data warehouse projects?

Answer 13

1. Because data warehouses are used to manage information crucial for strategic decision-making processes
2. Multi-dimensional properties and aggregation offer the opportunity to infer information from data.
3. There is a huge amount of information exchange over a network in the data-staging phases

Question 14

Which 2 control systems are important in data warehouses?

Answer 14

1. Management control systems

2. Auditing control systems.

Question 15

1.9.3 Evoltion what?

Answer 15

Figure out what the text means.