\sectionExercise 5: Weak Entity Example (Order-Item) \textbfScenario: \\ An e-commerce system has orders and line items. \beginitemize \item \textbfOrder: order\_number (PK), order\_date, customer\_name. \item \textbfLine Item: item\_number (only unique per order), product\_name, quantity, price. \item A line item cannot exist without an order. The combination (order\_number, item\_number) uniquely identifies a line item. \enditemize
\sectionExercise 6: Supertype/Subtype (Generalization) \textbfScenario: \\ A vehicle rental system tracks vehicles. A vehicle can be either a Car or a Truck. \beginitemize \item All vehicles have: VIN (PK), make, model, year. \item Cars have: number of doors, fuel type. \item Trucks have: cargo capacity (tons), number of axles. \enditemize entity-relationship diagram exercises and answers pdf
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