7. The following relation represents a fact table in a data warehouse (relational OLAP) of a company that sells markers for white boards. The SALES attribute represents the total value of makers of the respective color sold in the given year, and constitutes the "fact" of interest.

COLOR YEAR SALES

red 2013 2000

red 2014 1400

blue 2013 2600

blue 2014 5500

black 2013 5000

black 2014 6000

a) (1 points) A "data cube" of how many dimensions is represented? Give a brief explanation.

b) (2 points) Draw the "data cube" for the above fact table.

c) (1 points) Create aggregates along single dimensions for the maximum (MAX) as aggregation function, and add to the data cube in b).

8. Can a data warehouse that is separate from one or more operational databases improve performance, even if a relational table is used for storage? Give a brief explanation.