When creating the star schema models below, be sure to designate an appropriate primary key for each fact table and dimension table.

a$)$ Star Schema with Aggregated Fact Table: Using the data shown above for the ZAGI Retail Company Scenario, create a dimensional model containing an aggregated fact table for Sales, where a fact table shows a summary of units sold and dollars sold for purchases of each product

in each store for different dates.

b$)$ Star Schema with Line$-$Item Detailed Fact Table: Next, create a new dimensional model containing a line$-$item detailed fact table that tracks Sales by stores, customers, products, and different dates. The fact table should include the units sold, the dollars sold for each line item of

each sales transaction, and the transaction time $($TTime$).$ Be sure to include an appropriate primary key for the fact table that identifies each row $($i$.$e$.,$ each sales transaction and each product in the sales transaction$).$

c$)$ Constellation of Line$-$Item Detailed Fact Tables: Now ZAGI needs to track Sales and Returns $($assume return information is available$).$ Create a star schema with two fact tables. One fact table should be a line$-$item detailed fact table just like the one described in question b above. The

second fact table should be a line$-$item detailed fact table that tracks Returns by products, customers, stores, and different dates. The additional fact table should include the units returned, the dollars returned for each line item of each return transaction, and the transaction time $($TTime$).$ Be sure to include an appropriate primary key for the fact table that identifies each row $($i$.$e$.,$ each return transaction and each product in the return transaction$).$