An organizer commissioned us to design a database for auction platform. They provide a

summary of requirements as below.

$$ An auction is identified by its auction id$.$ It is characterized by its name, location,

and duration. The duration is composed of start time, and end time. At least one

manager is required to oversee each auction, and managers may oversee multiple

auctions.

$$ A manager is identified by her$/$his manager id$.$ We also record her$/$his name,

phone number, job description and email. Note that a manager may have multiple

emails.

$$ A buyer is identified by her$/$his buyer id$.$ We also record the name, phone number,

address, and payment method. The address is composed of country, city, and

postcode. Note that a buyer may use multiple payment methods.

$$ A buyer must be invited by at least one manager. Moreover, each manager can

invite zero or more buyers.

$$ Buyers place orders to purchase products. Each buyer can place zero or more

orders. Each order is identified by its id$.$ We also record the order$$s timestamp and

total price. Each order must be placed by one buyer.

$$ An order must contain one or more purchased items. Thus, we also need to record

the number of items in an order.

$$ An item is identified by its item id$.$ Every item in the auctions is unique. We also

record its name, price, and description. The description is composed of the

produce year, $$who made it$$ and previous auction price.

$$ Each item must be displayed in one or more auctions. We store the available status

to avoid conflict. An auction can display one or more items. Thus, we also need to

record the number of items displayed.

$$ Every item in the auction is provided by the seller, but the seller may not want to

disclose personal information to the public. A seller can provide one or more items.

Each item must be provided by one seller. The seller is identified by seller id and

item id$.$ We also record her$/$his name and visible status.

$$ In order to ensure that every order is authentic, valid and error$-$free. Each order is

required to be signed by managers who handle the specific sold items. Every

manager can sign zero or more orders and be responsible for zero or more items.

Each item must be handled by a single manager.

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Can you please cross check the answer for this $?$