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Each department is managed by an employee admits

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Unformatted text preview: ors. ssn' PROFESSOR' year' quarter' teaches' cid' COURSE' (e) Professors can teach the same course in several semesters, and only the most recent offering must be recorded. Every professor must teach exactly one course. Every course must be taught by some professor. Solution: A binary relationship with a key and a participation constraint over the entity set professors and with a participation constraint over the entity set courses. year' quarter' ssn' cid' PROFESSOR' teaches' COURSE' Part 3 (15 pts) A company database needs to store information about employees (identified by ssn, with salary, phone, home address, and office address as attributes), departments (identified by did, with name and budget as attributes), and children of employees (with name and age as attributes). Employees work at departments. Each department is managed by an employee. A child must be identified uniquely by name when the parent, who is an employee, is known. You may assume that only one parent of any child works at the company. We are not interested in information about a child once the parent leaves the company. Draw an ER diagram that captures this information. Identify all key and participation constraints. Solution: Child is a weak...
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