The Metropolitan Housing Agency (MHA) is a non-profit organization that advocates the development and improvement of low-income housing. The MHA operates in a metropolitan area of approximately 2.2 million people in a midwestern city. The MHA maintains data about the location, availability, and condition of low-income housing in 11 different census tracts in the metropolitan area. Within the boundaries of these tracts are approximately 250 different buildings that provide low-income housing. On average, each building contains 25 apartments or other units.
The MHA keeps data about each census tract, including geographic boundaries, median income of the population, elected officials, principal businesses, principal investors involved in attributes in that tract, and other demographic and economic data. It also maintains a limited amount of data about crime. For each building, the MHA stores the name, address, size, owner(s)?s name and address, mortgagor(s)?s name and address, renovations and repairs, and avail-ability of facilities for handicapped people. In addition, the MHA keeps a list of each of the units within each building, including the type of unit, size, number of bedrooms, number of baths, kitchen and dining facilities, location in the building, and any special remarks. The MHA wants to maintain data regarding the average occupancy rates for each unit, but to date it has been unable to collect or store such data. The MHA does, however, keep data about whether a given unit is occupied.
The MHA serves as an information clearinghouse and offers three basic ser-vices. First, it works with politicians, lobbyists, and advocacy groups to support legislation that encourages the development of low-income housing through tax incentives, developmental zoning preferences, and other legislative inducements. To accomplish this, the MHA provides information about low-income housing to state, county, and city governments. Second, through speeches, seminars, displays at conventions, and other public relations activities, the MHA officials strive to raise the community?s consciousness about the need for low-income housing. Finally, the MHA provides information about the availability of low-income housing to other agencies that work with the low-income and homeless populations.
A. Make a list of possible entities for a database to support MHA?s information needs.
B. Construct an IDEF1X entity-relationships diagram for the entities in question A.
C. Name each relationship and ensure that you have correctly defined the minimum and maximum cardinalities.