Lecture 8
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Announcements
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1. Exam is next week thursday, in class 2-4PM
2. It is open notes and open books

Design Decisions:
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Entity or attribute?

Entity relationship diagrams - continued
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Students(RIN, fname, lname, email, address, gpa)
Key: RIN

Courses(CourseNo, abbr, name, credits)
Key: CourseNo, Abbr

Sections(crn, semester, year, capacity, courseno)
Key: crn

Rooms(id, number, building_abbr)
Key: id

Buildings(abbr, name, lat, long)
Key: abbr

Departments(code, name, mainoffice_roomid)
key: code

FacultyStaff(rin, fname, lname, address, position, email, department_code)
Key: rin

Majors(code, name)
Key: code


StudentMajors(rin, code) key: rin, code

StudentSections(rin, crn, grade) key: rin, crn

SectionRooms(crn, roomid) key: crn, roomid

SectionInstructors(crn, rin, role) ket: crn, rin

FacStaffRooms(roomid, rin, phoneno) key: roomid, rin

Collaborates(rin1, rin2) key: rin, rin


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Weak entites

If rooms is represented as a weak entity


FacStaffRooms(building_abbr, roomid, rin, phoneno) key: roomid, rin

Departments(building_abbr, code, name, mainoffice_roomid)

SectionRooms(crn, building_abbr, roomid) key: crn, roomid