I have the following paragraph:
The pet owner is responsible for the cost of the treatment given to a pet. The owner is invoiced for the treatment arising from each examination, and the details recorded on the invoice include the invoice number, invoice date, owner number, owner name and full address, pet number, pet name, and the details of the treatment given. The invoice provides the cost for each type of treatment and the total cost of all treatments given to the pet. Additional data is also recorded on the payment of the
invoice, including the date the invoice was paid and the method of payment (for example, check, cash, visa). The invoice number is unique throughout the practice.
From this I have deduced that there are two entities; the invoice and the payment of the invoice. Can anyone advise me if this is correct?
Also this paragraph:
Each clinic also maintains a stock of pharmaceutical supplies (for example, antibiotics, pain killers). The details of pharmaceutical supplies include a drug number and name, description, dosage, method of administration, quantity in stock (this is ascertained on the last day of each month), reorder level, reorder quantity, and cost. The drug number uniquely identifies each type of pharmaceutical supply. The drug number is unique for each pharmaceutical supply and used throughout the practice.
From this I have deduced that there are two entities; the pharmaceutical supplies, and the order. Or could the maintenance of pharmaceutical supplies simply depend on the reorder level as a weak entity?
Any help appreciated.