You have been hired by A Real Estate Company (AREC). They are a national real estate company that has built their success by selling high-end houses to wealthy clients. They have branch offices in almost every major city across the United States. However, they have grown quickly and their business practices are fairly inefficient. They are still using paper files and have only recently invested in a computer system that will allow all of their branches to be networked together in order to share information. However, they have no experience in this area and have hired you to help them organize the database for this new system.
They have told you that they are interested in storing information about each of their branch offices. Each branch has a branch name to identify the area that it serves (i.e. AREC – New River Valley). For each branch they would want to store the branch name, as well as the branch street address and the year that that particular branch office was established. They also want the name and phone number of the head manager for each branch office. A manager would never manage more than one branch office at a time.
They also want to store contact information (name, phone) for all of the real estate agents who work at the branches. They’ve also decided that it would be a good idea to record the date that each agent was hired by the AREC branch. A real estate agent would be assigned to work for one branch; they don’t move around between branches.
Real estate agents are responsible for finding properties to list through their AREC branch office. They are supposed to look for high-end properties that are in good condition and will sell quickly. An agent’s pay is partly dependent on the number of properties they can list. Therefore, AREC wants to be sure that for each property listing they can identify which agent was responsible for listing the property.
AREC would obviously want to keep track of the details of the properties that their agents have listed. For any property listing that an agent gets, they would record the property address and information about the number of bedrooms, number of bathrooms, square footage, the listing date, and the original asking price.
They also want to record information (names and phone numbers) about the owners of the property that they list. It is possible for more than one person to be the owner of a piece of property. Because each owner may have a different amount of equity in the property, AREC also wants to know the percentage of the property that each person owns. Sometimes an owner will own several pieces of property that they will ask AREC to help them sell.
If, by some chance, AREC is asked to sell the same piece of property more than once (i.e. they sell it once, and after a few years the new owners wish to sell through AREC), they treat it as a different property listing.
They do this because they have found that the details of the house may have changed due to construction, etc.
(i.e. the square footage and number of bedrooms has increased) and it’s just easier to enter it all in as a new listing.
Draw an entity-relationship model (including modality, cardinality, relationship names, primary keys, foreign keys, etc.) for this example. This diagram should keep track of everything that was being recorded in the paper files and it should address any problems that may have been described in the scenario. Write on your diagram (or a separate sheet of paper) ANY assumptions that you made in your diagram. However you cannot make assumptions that contradict any information provided to you in this scenario.