You need to create relationships to meet the reporting requirements of the customer service department.

an additional date table named ShipDate, a one-to-many relationship from

Sales[sales_date_id] to Date[date_id], and a one-to-many relationship from

Sales[sales_ship_date_id] to ShipDate[date_id]

an additional date table named ShipDate, a many-to-many relationship from

Sales[sales_date_id] to Date[date_id], and a many-to-many relationship from

Sales[sales_ship_date_id] to ShipDate[date_id]

a one-to-many relationship from Date[date_id] to Sales[sales_date_id] and another one-to-many relationship from Date[date_id] to Weekly_Returns[week_id]

a one-to-many relationship from Sales[sales_date_id] to Date[date_id] and a one-to-many

relationship from Sales[sales_ship_date_id] to Date[date_id]

a one-to-many relationship from Date[date_id] to Sales[sales_date_id] and another one-to-many relationship from Date[date_id] to Sales[sales_ship_date_id]