Please answer the following questions. You need to draw ER diagrams using any free tools discussed in the class or you may draw using pencil and paper.

• Please identify the entities and relationships between them.
• For each entity, please identify the attributes each entity has.
• For each attribute, please identify whether this attribute is optional or required, single valued or multi-valued, simple or composite, stored or derived.
• Define a key (identifier) for each entity. Note that a key can contain multiple attributes (composite key).

1. A company has a number of employees. The attributes of EMPLOYEE include Employee ID (identifier), Name, Address, and Birthdate. The company also has several projects. Attributes of PROJECT include Project ID (identifier), Project Name, and Start Date. Each employee may be assigned to one or more projects or may not be assigned to a project. A project must have at least one employee assigned and may have any number of employees assigned. An employees billing rate may vary by project, and the company wishes to record the applicable billing rate (Billing Rate) for each employee when assigned to a particular project.