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The Student Database

The Student Database. The Selection Operator . Give me information of students under the age of 18  age<18 (Student). The Projection Operator  . Give me the name, address, and GPA of all the students  name, addr, GPA (Student)  name, GPA, addr (Student) . Sample Query.

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The Student Database

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  1. The Student Database

  2. The Selection Operator  • Give me information of students under the age of 18 • age<18(Student)

  3. The Projection Operator  • Give me the name, address, and GPA of all the students • name, addr, GPA(Student) • name, GPA, addr(Student)

  4. Sample Query • Give me the SID and GPA for students under the age of 18 • sid, GPA(age<18(Student))

  5. The Cross Product Operator  • Give me all combinations of students and the enrollment of students • Student  Enroll = (Student.sid, name, addr, age, GPA, Enroll.sid, dept, cnum, sec)

  6. Selecting on Cross Products • Give me all the information of enrolled students • Student.sid = Enroll.sid(Student  Enroll)

  7. Sample Query • Give me the name and addresses of students taking CS courses whose GPA is below 3.0 • name, addr(dept = ‘CS’  GPA < 3.0  Student.sid = Enroll.sid(Student  Enroll))

  8. The Join Operator • Class Enroll •  Class.dept = Enroll.dept  Class.cnum = Enroll.cnum  Class.sec = Enroll.sec(Class  Enroll)

  9. The Theta-Join Operator  • Class Class.cnum = Enroll.cnum  Enroll.dept = ‘CS’ Enroll • Class.cnum = Enroll.cnum  Enroll.dept = ‘CS’(Student  Enroll)

  10. The Union Operator  • Give me the SIDs of all students • sid(Student  GradStudent)

  11. The Set-Difference Operator – • Give me the department, course number, and section of all classes without any enrolled students • dept, cnum, sec(Class) – dept, cnum, sec(Enroll)

  12. The Set-Intersection Operator  • Give all the instructors who teaches both CS and EE classes • instructor(dept=’CS’(Class)) instructor(dept=’EE’(Class))

  13. The Rename Operator  • Give me pairs of student names who live at the same address • R.name > S.name(name, name(R.addr = S.addr(R(Student) S(Student) ) ) )

  14. The Division Operator / • Give me the SIDs of students who are enrolled in all of the CS classes • sid(Student) – sid(sid(Student dept, cnum, sec(dept=’CS’(Class))) – Enroll)

  15. The Division Operator / • Give me the SIDs of students who are enrolled in all of the CS classes • sid(Student) – sid( sid(Student)  dept, cnum, sec(dept=’CS’(Class)) – Enroll) )

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