ERD Business Rules (draw an ERD for each business) 130% ). A real estate firm has a number of sales offices in several states. Attributes of the sales office include OfficeNum and SO_Location. Each sales office is assigned at least one employee. Attributes of the employee include Emp_Id and Emp_name. An employee must be assigned to only one sales office. There is always one employee assigned as manager (all managers are employees) to manage the employees in their office. An employee may manage (Mgr_id) the employees only in the sales office to which (s)he is assigned. The sales office may list properties for sale. Attributes of the property include Property_id and PLocation. A listed property is for one office only. Each unit of property has one or more owners. Attributes of owners are Owner_id and Owner_name. An owner owns one or more units of property. The Percent_owned by the owner is recorded for each unit