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Unformatted text preview: 10 Chapter 2 Answer 2.3 The ER diagram is shown in Figure 2.1. Exercise 2.4 A company database needs to store information about employees (iden- tified by ssn , with salary and phone as attributes), departments (identified by dno , with dname and budget as attributes), and children of employees (with name and age as attributes). Employees work in departments; each department is managed by an employee; a child must be identified uniquely by name when the parent (who is an employee; assume that only one parent works for the company) is known. We are not interested in information about a child once the parent leaves the company. Draw an ER diagram that captures this information. Answer 2.4 Answer omitted. Exercise 2.5 Notown Records has decided to store information about musicians who perform on its albums (as well as other company data) in a database. The company has wisely chosen to hire you as a database designer (at your usual consulting fee of $2500/day). Each musician that records at Notown has an SSN, a name, an address, and a phone number. Poorly paid musicians often share the same address, and no address has more than one phone. Each instrument used in songs recorded at Notown has a unique identification number, a name (e.g., guitar, synthesizer, ﬂute) and a musical key (e.g., C, B-ﬂat, E-ﬂat). Each album recorded on the Notown label has a unique identification number, a title, a copyright date, a format (e.g., CD or MC), and an album identifier. Each song recorded at Notown has a title and an author. Each musician may play several instruments, and a given instrument may be played by several musicians. Each album has a number of songs on it, but no song may appear on more than one album....
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This note was uploaded on 10/18/2009 for the course INFS 614 taught by Professor Staff during the Fall '08 term at George Mason.
- Fall '08