EXERCISE using draw.io

Consider an online auction database system in which members $($buyers and sellers$)$

participate in the sale of items. The data requirements for this system are summarized as

follows:

Members

The online site has members who are identified by a unique member id and are

described by an email address, their name, a password, their home address, and a

phone number.

Supertype and Subtypes for Members

A member may be a buyer or a seller, but not both $($disjoint subtype$).$ A member must be one or the other $($mandatory or required participation$).$ A buyer has a shipping address recorded in the

database. A seller has a bank account number and routing number recorded in the

database. Both buyer and seller subtypes $($entities$)$ share the primary key with members which is membered.

Items

Items are placed by a seller for sale and are identified by a unique item number

assigned by the system. Items are also described by an item title, an item description,

a starting bid price, bidding increment, the start date of the auction, and the end date

of the auction. Items also have a classification attribute which classifies the item as a type.

Many to many relationship

Buyers place one to many bids on items.$$ Items have one to many bids from buyers.$$ This is a many to many relationship and you need to add a $$linking$$ or $$Associative$$ third table between Items and Buyers with a TransactionID $($primary key$)$ membered $($from the buyertable$)$ foreign key, ItemID $$ foreign key, and a bidding price and date$/$time stamp of the bid.