Try for E R Diagram

Activity 1
• In this exercise you are going to model and implement the database-part of a (simplified) CD-archive.
• Requirements
• These are the requirements for your CD-archive:
• 1. A CD is published in a given year by a record company. The CD has a title.
• 2. A CD contains songs with a certain length and one or more artists plays and sings on it.
• 3. An artist is either a band or a person. A band is composed of multiple persons.
• 4. We assume that a person can’t be a member of more than one band, but a person might be an artist on his/her own as well.
• 5. An artist has a nationality.
• 6. A song is composed by one or more persons. It is interesting to know when a song
was composed.
• 7. A song could be recorded on multiple records, generally with other artists than the
composer (cover-tunes).
• 8. The length of each of the songs on a CD must be possible to retrieve.
• 9. To be able to pose questions to the record companies it is important to store contact
information (email and phone no.) in the system
Activity2:
• 1) Construct an E-R diagram for a car-insurance company whose customers own one of more cars each. Each car has associated with it zero to any number of recorded accidents.
• (2) Construct an E-R diagram for a hospital with a set of patients and set of medical doctors. Associate with each patient a log of the various tests and examinations conducted.
• Activity3:
• Consider a university database for the scheduling of classrooms for final exams. This database could be modeled as the single entity set exam, with attributes course-name, section-number, room-number, and time. Alternatively, one or more additional entity sets could be defined, along with relationship sets to replace some of the attributes of the exam entity set, as
• Course with attributes name, department, and c-number
• Section with attributes s-number and enrollment, and dependent as a weak entity set on course
• Room with attributes r-number, capacity, and building
• (a) Show an E-R diagram illustrating the use of all three additional entity sets listed
• (b) Explain what application characteristics would influence a decision to include or not to include each of the additional entity sets.