CS 474, Spring 2016 Midterm Exam #2

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1 CS 474, Spring 2016 Midterm Exam #2 Name: By writing your name, you acknowledge the following honor code statement: I have neither given nor received unauthorized assistance on this examination. Directions 1. This is a closed-book, closed-notes, no-calculator exam. Do not refer to any materials other than the exam itself. 2. Do not look at anyone else s exam. Do not talk to anyone but the instructor during the exam. Turn off all cell phones, etc. 3. If you have a question, please come to the front of the room. If you need to leave the room, you must first ask for permission. 4. You will have 50 minutes to complete the exam. Please write clearly and show all your work. Problem Maximum Score Total 50 Note: You have 10 minutes per page (1 minute per point).

2 Problem 1: Multiple Choice When creating functions in SQL, which option tells the query optimizer that it s possible to reuse results instead of calling the function again? Ans = D A. IF EXISTS B. LANGUAGE SQL C. RETURNS TABLE D. STABLE STRICT E. VOLATILE As an embedded database engine, SQLite does not need to support A. ACID transactions B. command-line tools C. GRANT and REVOKE D. indexes and optimization E. terabyte-sized databases If X Q, then A. for every unique Q, there will be a unique X B. for every unique X, there will be a unique Q C. Q is functionally dependent on every subset of X D. Both A and B E. Both B and C Which of the following is NOT an example of a window query? A. calculate a running total B. compute a moving average C. get the current row number D. perform ranking by category E. select the maximum value Which of the following statements is NOT correct? A. views allow the user to store/run any SQL statement B. both views and functions may return a table of results C. functions can be written in languages other than SQL D. views and functions are referenced in a FROM clause E. unlike views, functions require a list of parameters Ans = C Ans = B Ans = E Ans = A

3 Problem 2: Third Normal Form Consider the relation R(A, B, C, D, E) with FD s AB C, C D, D B, and D E. a. (3 pts) Find all minimal keys for this relation. A needs to be in the key, since it s not on the right side. {AB} + = {A, B, C, D, E} {AC} + = {A, C, D, B, E} {AD} + = {A, D, B, E, C} {AE} + = {A, E} Therefore, AB, AC, and AD are the only minimal keys. b. (2 pts) Which of the FD s violate 3NF and why? Because {A, B, C, D} are prime, only D E violates 3NF. c. (3 pts) Decompose R into 3NF. Justify your answer. R 1 (A, B, C) R 2 (C, D) R 3 (D, B) R 4 (D, E) No need for a 5th relation, since R 1 is a superkey for R. d. (2 pts) Which of the 3NF relations are also in BCNF? R 2, R 3, and R 4 because they all have two attributes. R 1 is not because of the (transitive) dependency C B.

4 Problem 3: Views and Indexes a. (6 pts) Suppose the relation R(a, b, c) has the tuples shown below. What tuples are generated by the view? What is the result of the aggregation query? (Don t forget to include the schema in your answers.) R a b c CREATE VIEW V AS SELECT a+b AS d, c FROM R; SELECT * FROM V; d c SELECT d, sum(c) FROM V GROUP BY d HAVING count(*) <> 1; d sum b. (4 pts) Consider the query from HW3 below. Write CREATE INDEX statements (one for each table) that define the indexes used in the following execution plan. SELECT p.name AS real_name, c.name AS char_name FROM movie AS m JOIN cast_info AS i ON m.id = i.movie_id JOIN person AS p ON i.person_id = p.id JOIN character AS c ON i.char_id = c.id WHERE m.title = The Lego Movie AND m.kind_id = 1 CREATE INDEX ON movie (title); AND m.year = 2014 AND i.role_id <= 2 CREATE INDEX ON cast info (movie id); ORDER BY i.nr_order; CREATE INDEX ON character (id); CREATE INDEX ON person (id);

5 Problem 4: 3-Tier and JDBC a. (5 pts) Recall the web applications we discussed in class (e.g., HW5: Dynamic Charts). For each of the following tiers, identify the programming language and the server/client software that executes that part of the application. Tier Language Software Data SQL PostgreSQL (db server) Logic Java/PHP Tomcat (app server) GUI HTML/JS Chrome (web browser) b. (5 pts) The following Java code executes a simple query. Fill in the blanks. final int div_num = 113; String sql = "SELECT div_name FROM division WHERE div_num =?"; db = Database.open(); st = db.preparestatement(sql); Connection PreparedStatement st. (1, div_num); setint while (rs.next()) { rs = st.executequery(); ResultSet String div_name = rs. ; getstring(1) System.out.println(div_name); }

6 Problem 5: Advanced Topics a. (3 pts) What privileges are needed to execute the following query? Write the GRANT statements that would give those privileges to the student user. DELETE FROM ships WHERE name IN ( SELECT ship FROM outcomes WHERE result = sunk ); GRANT DELETE ON ships TO student; GRANT SELECT ON outcomes TO student; b. (4 pts) Consider the following relation that represents organizations at. What is the result of the recursive query? (Hint: There are 14 rows, and don t forget the ORDER BY.) org parent child CS ENGR GEOG IA WITH RECURSIVE report AS ( SELECT parent, child FROM org UNION SELECT r.parent, o.child FROM report AS r, org AS o WHERE r.child = o.parent ) SELECT * FROM report ORDER BY parent, child; parent child CS ENGR GEOG IA GEOG IA CS ENGR GEOG IA c. (3 pts) Given the text search vector below, what is the most likely original string? 474 :2 applic :6 cs :1 databas :3 design :4 CS 474: Database Design and Application

6 February 2014 CSE-3421M Test #1 w/ answers p. 1 of 14. CSE-3421M Test #1. Design

6 February 2014 CSE-3421M Test #1 w/ answers p. 1 of 14 CSE-3421M Test #1 Design Sur / Last Name: Given / First Name: Student ID: Instructor: Parke Godfrey Exam Duration: 75 minutes Term: Winter 2014 Answer