Example : Draw an EER diagram
organization depends on a number of different type of persons for its successful operation . The organization is interested in the following attributes for all of these persons : SSN , Name , Address and Telephone . A person may have multiple numbers . Three types of persons are of greatest interest : employees , volunteers and donors . Employees only have a Date Hired attribute and volunteers only have a Skill attribute . Donors only have a relationship ( name Donates ) with an item that has number and name . A donor must have donated one or more items , and an item may have no donors or one donor .
There are persons other than employees , volunteers and donors who are interest to the organization so that a person need not belong to any of these three groups . On thee other hand at a given time a person may belong to two or more of these groups ( for example , employees and donors ).
Draw an EER diagram based on the requirements above . write down assumptions ( if any ) you make in yours answer .
