Product- an item made available for sale.
Promotion- a special incentive provided to the customer.
Service- a job performed by one of Petries associates.
Transaction- record that a particular product or service was sold to a specific customer. Purchase- a unique number used to identify a purchase.
Each identifier was chosen for the following reasons:
Must be a noun
Follows a standard format
Similar but distinguishing names
States what the attribute is and why it is important
4. These are drawn in problem 1 in the dia diagram. One-to-many includes customer to coupon, customer to purchase, customer to transaction, product to purchase and employee to transaction. Zero-to-many includes customer to promotion and product to transaction. Customer to report is a one-to-one.
5. The entity Employee does not play an important role in Petries case. It is necessary for an employee to be present to make changes to a transaction. Considering an ER diagram design from a database point of view, the transactions are monitored by the database admin. The absence of this entity does not have any great consequence.
7.Coupon_Expiry_Date, Transaction_Date, Report_Date, Purchase_Date, Promotion_Expiry Date.
Attributes must be kept to keep track of historic time and maintain records for later reference.