Question

You are hired to create a database for a Real Estate firm that lists and sells properties at multiple sales offices . Draw an ER diagram using ERDPlus for the following description of the firm, indicate all primary keys and cardinalities. List any assumptions you made.

There are many sales offices in several states. Attributes of a sales office include office number (identifier) and location. Components of location include Address (number & street), City, State and Zip.

Each sales office is assigned one or more employees. Attributes of employees include employee ID (identifier), employee name and phone number. An employee must be assigned to only one office

Each sales office has one employee assigned to manage that office. An employee may manage only the sales office he or she is assigned.

A sales office lists properties for sale. A sales office may have any number of properties listed or may have no properties listed. Attributes of property include Property ID (identifier), Property type and location. Components of location include Address (number & street), City, State and Zip.

When a property is listed the date of the listing and the price is recorded. A property may be listed multiple times but the dates must be unique.

Each unit of property has one or more owners. Attributes of owners are Owner ID (identifier) and Owner name. An attribute between property and owner is Percent Owned.

Answer 1

ER diagram in Chen Model designed using the online tool as specified in the question

Relational schema diagram converted from the ERD using the same online tool