Question 1 (40 points) E-R model

The Tower is an apartment rental company that would like to create an on-line management system to keep track of apartment complex units, tenants, maintenance requests, and the rental payment information. Since you are taking a database class, you are asked to assist the company in designing a database based on the following specifications.

Each apartment unit has a unique number. Each units street number, street name, city, state, zip code, number of bedrooms, monthly rent, and occupancy status are recorded.

Each tenant must lease at least one apartment unit for a period of time. It is important to document the lease start date and end date.

The Tower tracks each tenants name, SSN, home mailing address, and phone number. Each tenant is assigned a unique identifier number.

Each tenant should pay the monthly rental fee by the first day of each month. Any rent due not paid by the 4th day of the monthly rental period is subject to a $50.00 late fee charge with an additional $10.00 for each late day. Accurately documenting payment information is vital for deciding the late payment penalties. Each payment date, amount, pay type (cash, check, credit card, etc.) need to be tracked. Each payment has a unique identifier number.

To ensure each unit is in a livable condition, each tenant may request work orders for maintenances. The requested date and problems should be recorded for each work order. In addition, each work order has a unique identifier number, completed date and workers name. Once the repair job is complete, the work order can be signed off.

Specifically, your tasks are:

Draw an ER-diagram (in a DIA EDITOR) for the database by identifying the entity sets, relationship sets and their multiplicity, and the primary key for each entity set (and weak entity set, if any) and each relationship set.