STUDENT std_id fname lname address gender grade class_president school_id. STAFF sid fname lname bdate gender Salary role school_id

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1 CSI2132: Database I Winter 2017 Assignment 3: Due 8 th April, 11:59 pm through Blackboard Covers: Advanced Relational Algebra, Normalization, Storage and Indexing. (5 %) Submit your assignment as a PDF file. Part 1: Relational Calculus Following is a relational database schema SCHOOL_DB = {STUDENT, STAFF, SCHOOL, SCHOOL_BOARD, ACTIVITY, PARTICIPATE}. In each relation schema, the underlined attribute represents the primary key. STUDENT std_id fname lname address gender grade class_president school_id STAFF sid fname lname bdate gender Salary role school_id SCHOOL school_id school_name school_head_id SCHOOL_BOARD school_id school_board_name ACTIVITY act_id act_name act_date school_id PARTICIPATE std_id act_id Ranking Specify the following queries on the SCHOOL_DB relational database schema using the relational operators. a. Retrieve the maximum grade of Westboro School students who got ranking more than 4 in the Art activity that they are participating in. b. List the names of all school heads who have staff in their school with the same first name as themselves. c. For each activity, list the activity name and the minimum ranking of each activity. d. For each school, retrieve the school name and the average salary of all staff working in that school. e. Retrieve the names of all students who participate on every activity. f. Retrieve the names of all students who do not participate on any activity.

2 Part 2: Normalization 2.1: Consider the relation R = {A, B, C, D, E, F} and the following set of functional dependencies F = {{A C, F}, {C D}, {B E}} a. Determine which sets of attributes form the key of R. b. What normal form is the relation in? Explain your answer. c. Normalize your relation until no more decomposition is possible. State the reasons behind each decomposition 2.2: Consider the relation R = {A, B, C, D, E} and the following set of functional dependencies F = {{A D}, { B C}, {A, B E}} a. Is this relation in 3NF? Why? b. Is this relation in 2NF? Why? 2.3 Consider the following requirements for a university database to keep track of students progress: 1. The student information stored is: student s name (Sname), student number (Snum), Social Security number (Ssn), current address (St_addr) and phone (St_phone), birth date (Bdate), sex (Sex), class (Class) ( freshman, sophomore,, graduate ), major department (Major_code), minor department (Minor_code) (if any), and degree program (Prog) ( b.a., b.s.,, ph.d. ). Both Ssn and student number have unique values for each student. 2. Each department is described by a name (Dname), department code (Dcode), office number (Doffice), office phone (Dphone), and college (Dcollege). Both name and code have unique values for each department. 3. Each course has a course name (Cname), description (Cdesc), course number (Cnum), number of semester hours (Credit), level (Level), and offering department (Cdept). The course number is unique for each course. 4. Each section has an instructor (Iname), semester (Semester), year (Year), course (Sec_course), and section number (Sec_num). The section number distinguishes different sections of the same course that are taught during the same semester/year; its values are 1, 2, 3,, up to the total number of sections taught during each semester. 5. A grade record refers to a student (Ssn), a particular section, and a grade (Grade).

3 Answer the following questions: a. Show all the functional dependencies that should hold among the attributes. b. Design relation schemas for the database that are each in 3NF or BCNF. c. Specify the key attributes of each relation. 2.4: BUY (trx _id, trx _date, items, cards) This relation refers to a supermarket transaction made by a customer. The transaction has a single transaction date (trx _date) but involves many items and one may use multiple credit cards. i.e. The TRIP relation has the following FDs and MVDs: trx_id start_date trx _id items trx _id cards Normalize the relation to be in 4NF.

4 Part 3: Storage and Indexing 3.1 A file has r = 40,000 STUDENT records of fixed length. Each record has the following fields: std_id fname Lname address gender grade class_president school_id Std_id (6 bytes), fname (25 bytes), lname (25 bytes), Address (40 bytes), gender (1 byte), grade (4 bytes), class_president (6 bytes), school_id (6 bytes). An additional byte is used as a deletion marker. The disk has the following parameters: Seek time 20 mesc, relational delay 10 mesc, block transfer time 1 mesc, block size 2400 bytes and inter block gap size 600 bytes. a. Calculate the record size R in bytes. b. Calculate the blocking factor bfr and the number of file blocks b, assuming an unspanned organization. c. Calculate the average time it takes to find a record by doing a linear search on the file if i. the file blocks are stored contiguously, and double buffering is used; ii. the file blocks are not stored contiguously. 3.2 Assume that in the above relation, that the following fields are of fixed-length: std_id, gender, grade, class_president and school_id each 10 bytes long. Whereas, the following fields are of variable-length: fname, lname and address. If pointers within a record require 4 bytes, and the record length is a 4-byte integer, how many bytes, exclusive of the space needed for the variable-length fields, are needed for the record? You may assume no alignment of fields is required. 3.3 The following is order 2 B+ trees and the data records that it points to: Show the B+ tree that results after a. What will happen after inserting 10* b. What will happen after deleting 24*

5 3.4 Reference to the School_DB, consider (un-normalized) version that contains the following relation: Participate_In_Activity (std_id, name, address, school_id, act_id, act_date, ranking) A student is identified with a unique std_id, and has only one address. students can have multiple activities, but they always have different activity dates. The student can have different rankings on different activities but only one ranking per activity. Assume that the following four SQL commands are known to be frequent (with actual parameters substituted in for?): 1. SELECT DISTINCT name, address FROM Participate_In_Activity WHERE std_id =?; 2. SELECT * FROM Participate_In_Activity WHERE std _id =? AND act_date >?; 3. SELECT std_id, ranking FROM Participate_In_Activity WHERE ranking BETWEEN? AND?; a) Suggest one or more indexes, taking into account of the above. b) State the indexed attributes for each index, along with the index type (primary or secondary). 3.5 Suppose that we are using extendable hashing on a file that contains records with the following search-key values: 2, 3, 5, 7, 13, 17, 19, 23, 29, 32 Show the extendable hash structure for this file if the hash function is h(x) = x mod 8 and buckets can hold three records.