Q$3.$

$(25$ points$)[$OLAP Operations$]$

Assume we have a data cube with the following three dimensions: Store, Time, and Product. The values $($i$.$e$.,$ facts$)$ represent the total number of items sold. Draw an example multidimensional cube that shows these three dimensions $($City$,$ Quarter, Product$).$ It should include all quarters in $2024$ and include the following cities: Toronto, New York, London, and Paris. The products being sold are TV$,$ Tablet, Laptop, and Monitor.

Hint: Only display the values for the dimensions that are visible from your chosen perspective. For instance, if you cannot show the internal cells of the cube in your drawing, focus on the outermost layer or surface $($i$.$e$.,$ the cities, quarters, and products you can represent$).$

The hierarchy for the dimensions is as follows:

$-$ Store: Country $\backslash (\backslash$rightarrow $\backslash )$ City

$-$ Time: Year $\backslash (\backslash$rightarrow $\backslash )$ Quarter

$-$ Product: Category $\backslash (\backslash$rightarrow $\backslash )$ Item $($in this case, only individual items are given, i$.$e$.,$ TV$,$ Tablet, Laptop, and Monitor$)$

OLAP Operations:

What OLAP operations should be performed to answer the following questions? $($Hint: For Question $1,$ perform a roll$-$up operation to aggregate data across all four quarters for $2024).$

$1.$ Total number of items sold for each product in each city in $2024.$

$2.$ Total number of TVs sold in Q$22024$ across all cities $($focus only on the TV product$).$

Show the result of each OLAP operation as a $2$D table $($for Question $1)$ or a $1$D vector $($for Question $2)$ and a bar chart.