Database Management Systems (CS 601) Assignments

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1 Assignment Set I : Introduction (CO1) DBA s are the highest paid professionals among other database employees -Justify. What makes a DBA different from the other SQL developers? Why is the mapping between different schema level important. Assignment Set II: External Sorting (CO1) In this problem you will estimate the running time to sort a file with N = 106 pages. Assume that we have a disk with an average seek time of 10ms, average rotation delay of 5ms and a transfer time of 1ms for each page. Assume the cost of reading/writing a page is the sum of those values (i.e. 16ms) for Q3.1 and Q3.2. [Q3.1] Find the total running time using the two-way external merge sort (with three buffer pages). Follow the analysis and formulas in chapter 13.2 (p.423). [5 points] [Q3.2] Find the total running time using 255 input buffer pages and 1 output buffer page (B = 256). Follow the analysis and formulas in chapter 13.3 (p.424). [10 points] [Q3.3] The basic idea of blocked I/O is to read/write multiple pages (which we call a buffer block) at a time while performing sorting. In this case, the cost of reading/writing a buffer block of b pages is 1 random disk access for the first, and b-1 sequential disk accesses for the rest. Thus, the cost is the average seek time plus the average rotation delay (to locate the first page) plus 1ms per page (data transfer). Assume each buffer block consists of 32 pages (b = 32), and we use 7 input buffer blocks and 1 output buffer block (so still B = 256), find the total running time. Follow the analysis and formulas in chapter (p.430). [15 points] Assignment Set III: Hashing (CO3) Assume we have the following records where we indicate the hashed key in parenthesis (in binary): a [000000] b [001100] c [100001] d [010010] e [111111] f [010010] g [101101] h [001100] i [001100] Consider an extendible hashing structure where buckets can hold up to three records. Initially the structure is empty (only one empty bucket). Show the extendible hashing structure after these records (in the order shown above) have been inserted. Assume that as mentioned in the textbook, the directory doubles in size at each overflow. For the same records above, consider a linear hashing structure where buckets can hold up to three records. Initially the structure is empty (only one empty bucket). Show the linear hashing structure after these records (in the order shown above) have been inserted. Assume that we split whenever the new key goes into a full bucket (which may or may not be the split bucket). Department of CSE Page 4

2 Assignment Set IV: Functional Dependency 1) Specify all functional dependencies without redundancies (see definition of minimal sets of functional dependencies in section ) for each table of the library database. Then state which normal form (1NF, 2NF, 3NF or BCNF) each of the existing tables is, and why. 2) For each table that doesn t fulfill the requirements for BCNF, explain the problems that this lack of normalization has and their potential consequences. Give some examples. 3) Design a new database, with different tables, where all the tables fulfill BCNF without losing any information. (Refer -Elmasri/Navathe: chapters 10 and 3, sections 11.1 and 11.2.) Assignment Set V: Relational Algebra (CO2). Q1.i) Show how you may specify the following Relational Algebra operations in tuple relational calculus form. 2*1=2 a. A=C(R(A,B,C)) b. <A,B>(R(A,B,C)) ii) Find the results of these expressions for the relational schema R and S. R A B C D a. R S b. R R.C=S.CS c. R S S C D E Q2. Consider the given relations. Sailors (sid, sname,rating, age) Reserves (sid, bid, day) Boats (bid, bname, color) i) Write down the queries in its relational algebra form. a. Find the names of sailors who have reserved at least one boat. b. Find the colors of boats reserved by John. c. Find the names of sailors who have reserved all boats. ii) Write down queries in tuple calculus a. Find all sailors with rating above 7. b. Find the names & date of joining of the sailors who have reserved the boat named Interlake. Department of CSE Page 5

3 Assignment Set VI: ERD (CO2) 1. A Case study of Pine valley Furniture: The company sells a number of different furniture products. These products are grouped into several product lines. The identifier for a product is Product_ID, while the identifier for a product line is Product_Line_ID. A product line may group any number of products, but must group at least one product. Each product must belong to exactly one product line. Customers submit orders for products. A customer may submit any number of orders. Each order is submitted by exactly one customer. The identifier for a customer is Customer_ID. Pine Valley Furniture Company has several salespersons. A salesperson serves exactly one sales territory. Each sales territory is served by one or more salespersons. The company has over 100 employees. The identifier for employee is Employee_ID. An employee may have more than one skill. And each skill can be mastered by many employees or none. Each employee works in one or more work centers. Each employee has exactly one supervisor. Develop an extended ERD for the above mentioned system. Assignment Set VII: Normalization (CO3) Q1. Decompose the given table into its 4NF form. R (A B C D E F G H I J) with dependencies F= {AB C, A DE, B F, F GH, D IJ}. Q2. a) Consider a relation R (City, Street, Zip) with FD s F= {City, Street- Zip, Zip- City}. Prove whether the table is in BCNF or not. b) What is 4NF? Explain with an example. Q3. What are the needs for Normalization? Why functional dependency is important? Assignment Set VIII: SQL (CO3) 1. What is Stored Procedure? What is a view? 2. What is Trigger? 3. What is data ware housing & OLAP? 4. How many types of fragmentations are there? Explain how they are good as a backup? 5. Preventing distributed deadlock is very essential for a distributed system, justify you answer. Assignment Set IX: Application Design & Development (CO3) Testing for SQL-injection vulnerability: a. Suggest an approach for testing an application to find if it is Department of CSE Page 6

4 vulnerable to SQL injection attacks on text input. b. Can SQL injection occur with other forms of input? If so, how would you test for vulnerability? Assignment Set X: Transaction Management (CO4) In this problem, you are given three different workloads, each of which contains of a set of concurrent transactions (consisting of READ and WRITE statements on objects). For each workload, several different interleavings of execution are given. Your job is to indicate whether, for each of the five interleavings : The given interleaving has an equivalent serial ordering. If so, indicate what the serial ordering is. Whether the given interleaving would be valid using lock-based concurrency control. Assume that locks, when needed, are acquired (with the appropriate lock mode) on an object just before the statement that reads or writes the object and that all locks are released during the COMMIT statement (and no sooner.) If the interleaving is not valid, indicate whether or not it would simply never occur or would result in deadlock, and the time when the deadlock would occur. Whether the given ordering would be valid using optimistic concurrency control. If not, indicate which transaction will be aborted. Assume the use of the Parallel Validation scheme described in Section 5 of the Optimistic Concurrency Control paper by Kung and Robinson, and that the validation and the write phases of optimistic concurrency control happen during the COMMIT statement (and no sooner.) Assume in all cases that written values can depend on previously read values.(the workloads are shown next.) Workload 1 Transaction 1 READ A Transaction 2 WRITE B WRITE A Workload 2 Transaction 1 Write A Transaction 2 WRITE B Read C Interleaving 1: 1 T1: READ A 2 2 T2: READ A 3 3 T1: 4 T1: WRITE C 5 5 T2: WRITE B 6 6 T1: COMMIT 7 7 T2: WRITE A Department of CSE Page 7

5 8 8 T2: COMMIT Interleaving 2: 1 T1: READ A 2 T1: 3 T2: READ A 4 T2: WRITE B 5 T2: WRITE A 6 T2: COMMIT 7 T1: WRITE C 7 T1: COMMIT Interleaving 4: 1 T1: Write A 2 T2: Write B 3 T1: Read B 4 T2: Read C 5 T1: Commit 6 T2: Commit Interleaving 5: 1 T1: Write A 2 T2: Write B 3 T2: Read C 4 T2: Commit 5 T1: Read B 6 T1: Commit Department of CSE Page 8

A7-R3: INTRODUCTION TO DATABASE MANAGEMENT SYSTEMS

A7-R3: INTRODUCTION TO DATABASE MANAGEMENT SYSTEMS NOTE: 1. There are TWO PARTS in this Module/Paper. PART ONE contains FOUR questions and PART TWO contains FIVE questions. 2. PART ONE is to be answered