Identify appropriate entities, relationships, attributes, domains, and keys as well as all Specializations and generalizations:

i.e Identifying entities, relationships, attributes, domains, and keys:

Identify the main entities involved in the online auction system, such as users, items, auctions, sellers, etc. (Minimum of 7 entity types)

Determine the relationships between these entities

Define the attributes for each entity (Must be as complete as possible)

Determine the domains for each attribute, such as the data type, range of values, and constraints

Identify the keys for each entity