jeudi 26 février 2015

Identification of other entities.


Given the following scenario, what three other entities (and their attributes) would be of importance to this model?


SCENARIO:


The transport authority in Jamaica has recently added train transportation to the database of transportation through the assistance of overseas investors. They require a n updated database to store all the information on their trains, buses and personnel. They also want to keep track of delays and the number of travelers on a daily basis. Each train has an id number, type, production year and capacity. Employee information such is staffId, employment date, position and salary needs to be stored. Each bus has an id, capacity, type, number of kilometers on a full tank should be recorded. Bus drivers has id, name, dob, salary, hire_date. A bus driver does not drive a specific bus but may drive any bus. Each bus/ train makes a stop on each route. The sequence of stops on each bus/train route is needed. Each route has a unique route number and name.


For each route and departure time, on each day, record which physical train/bus was used (This is always a single bus or train - several trains can be coupled together). Timetable information is important as one need to know the planned arrival and departure times for each route and every stop. Timetable statistics which is the actual arrival and departure times for every bus/train, on every stop on every day is also required. Periodically surveys are being made that record the destinations of all travelers in a given bus/train at a given time (between two stops). Manning of the bus/train is important, therefore it should be taken into account who has worked on a particular vehicle at a given time, and this may change at any time during a route.


Information also needs to be stored about the supervisor in charge of each route. A route may have only one supervisor and a supervisor may be in charge of many routes. Bus/train drivers all have a supervisor to report to who may or may not be the supervisor of the route that they are manning.





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