CPSC 304 2004 MIDTERM 2 SOLUTIONS

CPSC 304 2004 MIDTERM 2 SOLUTIONS - CPSC304Midterm2...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CPSC 304 Midterm 2 Nov 10, 2004 Total: 17 points Question 1 (9 points) The donations relation was defined based on the following SQL statement: CREATE TABLE donations (recipientName CHAR(20) NOT NULL, donorOrganization CHAR(20) NOT NULL, organizationType CHAR(20), amount REAL, PRIMARY KEY (recipientName, donorOrganization) ) For each of the following relational calculus queries, determine if there exists an equivalent relational algebra statement. If you answer is positive, give such a statement; otherwise, just state that no such statement exists. (You may get part marks if you write down in English the correct meaning of each query.) a) { < N > | x, y (<N, x, tobacco, z > donations and <N, y, tobacco, r> donations and x y) } (2 points) Recipients who received donations from at least 2 distinct tobacco organizations. π A.recipientName A.recipientName =B.recipientName ° A.organizationType = tobacco ° B.organizationType = tobacco ° A.donorOrganization <> B.donorOrganization [ ρ A (donations) · ρ B (donations)] b) { < N > | x ( <r , x, tobacco, s > donations <N , x, tobacco, t > donations) }
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern