department may run a number of courses. All teaching staff are attached to departments, each staff member belonging to a unique department. (Note: see how many meanings you can assign to this ambiguous sentence). Every course is composed of subcourses. Some subcourses are part
Database Design CC204 May – Aug 2017 of more than one course. Staff may teach on many subcourses and each subcourse may be taught by a number of staff. Draw an entity-relationship model for this example. Show both cardinalities and optionalities. Put a question mark where the degree is not clear from the text. Don't assume anything; rather, write a list of questions you would have to find answers to complete the model. Entity Attr Multiplicity Faculty Department: 1…* 1…* put near department Department Course: 1…* Faculty: 1…1 Course Subcourse: 1…* Department:1…1 Subcourse Course:1…* Teaching staff: 1…* Teaching staff Department: 1…1 Subcourse: 1…*
Database Design CC204 May – Aug 2017 Exercise 3 - STUDENTS AND COURSES (Similar to Exercise 2) Draw an entity-relationship diagram for the following scenario, stating any assumptions you find it necessary to make, and showing unknown cardinalities and optionalities using question marks on the relationship line. Show also the attributes explicitly mentioned in the scenario and underline any you consider suitable candidates for being primary keys. It is required to keep the following information on students, courses and subcourses. Each student has a name, identification number, home address, term address, and a number of qualifications for which the subject (e.g. maths), grade (e.g. C) and level (e.g. `A' level) are recorded. Each student is registered for one course where each course has a name (e.g. Information Systems) and an identification number. Record is kept of the number of students registered for each course. Each course is divided into subcourses where a subcourse may be part of more than one course. Information on subcourses includes the name, identification number and the number of students taking the course.
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- Entity-relationship model, Database Design CC204