Consider the following relational schema:

 COURSES (cno, cname)
 STUDENTS (rollno, sname, age, year)
 REGISTERED FOR (cno, rollno) 

(a) Write a relational algebra query to
Print the roll number of students who have registered for cno 322.
(b) Write a SQL query to
Print the age and year of the youngest student in each year.

Consider the relation scheme.

 AUTHOR      (ANAME, INSTITUTION, ACITY, AGE)
 PUBLISHER   (PNAME, PCITY)
 BOOK        (TITLE, ANAME, PNAME) 

Express the following queries using (one or more of )SELECT, PROJECT, JOIN and DIVIDE operations.
(a) Get the names of all publishers.
(b) Get values of all attributes of all authors who have published a book for the publisher with PNAME = ‘TECHNICAL PUBLISHERS’.
(c) Get the names of all authors who have published a book for any publisher located in Madras.

Consider a relational database containing the following schemas.

The primary key of each table is indicated by underlying the constituent fields.

SELECT s.sno, s.sname
FROM Suppliers s, Catalogue c
WHERE s.sno = c.sno AND
              Cost > (SELECT AVG (cost)
                      FROM Catalogue
                      WHERE pno = ‘P4’
                      GROUP BY pno);

The number of rows returned by the above SQL query is

Consider the following relations A, B, C.

How many tuples does the result of the following SQL query contain?

SELECT A.id 
FROM A 
WHERE A.age > ALL (SELECT B.age 
                   FROM B 
                   WHERE B. name = "arun")

Which of the  following statements are TRUE about an SQL query?

P:An SQL query can contain a HAVING clause even if it does not have a GROUP BY clause.
Q:An SQL query can contain a HAVING clause even if it has a GROUP BY clause.
R: All attributes used in the GROUP BY clause must appear in the SELECT clause.
S: Not all attributes used in the GROUP BY clause need to appear in the SELECT clause

A library relational database system uses the following schema

USERS (User#, UserName, HomeTown)
BOOKS (Book#, BookTitle, AuthorName)
ISSUED (Book#, User#, Date) 

Explain in one English sentence, what each of the following relational algebra queries is designed to determine

(a) σ User #=6 (11 User #, Book Title ((USERS ISSUED) BOOKS))
(b) σ Author Name (BOOKS (σ Home Town) = Delhi (USERS ISSUED))) 

Consider the following database relations containing the attributes

Book_id 
Subject_Category_of_book
Name_of_Author
Nationality_of_Author 
with Book_id as the Primary Key. 

(a) What is the highest normal form satisfied by this relation?

(b) Suppose the attributes Book_title and Author_address are added to the relation, and the primary key is changed to (Name_of_Author, Book_Title), what will be the highest normal form satisfied by the relation?

Consider the following relational database schemes:

  COURSES(Cno, name)
  PRE-REQ(Cno, pre_Cno)
  COMPLETED(student_no, Cno) 

COURSES give the number and the name of all the available courses.
PRE-REQ gives the information about which course are pre-requisites for a given course.
COMPLETED indicates what courses have been completed by students.

Express the following using relational algebra:
List all the courses for which a student with student_no 2310 has completed all the pre-requisites.

(a) Suppose we have a database consisting of the following three relations.
FREQUENTS(student, parlor) giving the parlors each student visits.
SERVES(parlor, ice-cream) indicating what kind of ice-creams each parlor serves.
LIKES(student, ice-cream) indicating what ice-creams each parlor serves.
(Assuming that each student likes at least one ice-cream and frequents at least one parlor)
Express the following in SQL:
Print the students that frequent at least one parlor that serves some ice-cream that they like.

(b) In a computer system where the 'best-fit' algorithm is used for allocating 'jobs' to 'memory partitions', the following situation was encountered:

When will the 20K job complete? Note - This question was subjective type.

Consider the set of relations

EMP(Employee-no, Dept-no, Employee-name, Salary)
DEPT(Dept-no, Dept-name, Location) 

Write an SQL query to:
(a) Find all employee names who work in departments located at "Calcutta" and whose salary is greater than Rs. 50,000.
(b) Calculate, for each department number, the number of employees with a salary greater than Rs. 100,000.

Which of the following is/are correct?

Consider a bank database with only one relation
transaction (transno, acctno, date, amount)
The amount attribute value is positive for deposits and negative for withdrawals.

(a) Define an SQL view TP containing the information.
(acctno, T1.date, T2.amount)
for every pair of transactions T1, T2 such that T1 and T2 are transaction on the same account and the date of T2 is ≤ the date of T1.

(b) Using only the above view TP, write a query to find for each account the minimum balance it ever reached (not including the 0 balance when the account is created). Assume there is at most one transaction per day on each account, and each account has had atleast one transaction since it was created. To simply your query, break it up into 2 steps by defining an intermediate view V.

In SQL, relations can contain null values, and comparisons with null values are treated as unknown. Suppose all comparisons with a null value are treated as false. Which of the following pairs is not equivalent?

Given relations r(w, x) and s(y, z), the result of

    select distinct w, x
    from r, s  

is guaranteed to be same as r, provided

Consider a relation geq which represents “greater than or equal to”, that is, (x,y) ∈ geq only if y >= x.

create table geq
(  Ib integer not null
   ub integer not null
   primary key 1b
   foreign key (ub) references geq on delete cascade ) 

Which of the following is possible if a tuple (x,y) is deleted?

Consider the set of relations shown below and the SQL query that follows.

  Students: (Roll_number, Name, Date_of_birth)
  Courses: (Course number, Course_name, Instructor)
  Grades: (Roll_number, Course_number, Grade)
  select distinct Name
  from Students, Courses, Grades
  where Students. Roll_number = Grades.Roll_number
      and Courses.Instructor = Korth
      and Courses.Course_number = Grades.Course_number
      and Grades.grade = A 

Which of the following sets is computed by the above query?

Consider the following SQL query

   select distinct al, a2,........., an
   from rl, r2,........, rm
   where P 

For an arbitrary predicate P, this query is equivalent to which of the following relational algebra expressions?

The following relations are used to store data about students, courses, enrollment of students in courses and teachers of courses. Attributes for primary key in each relation are marked by ‘*’.

 Students (rollno*, sname, saddr)
 courses (cno*, cname)
 enroll(rollno*, cno*,grade)
 teach(tno*,tname,cao*) 

(cno is course number, cname is course name, tno is teacher number, tname is teacher name, sname is student name, etc.)

Write a SQL query for retrieving roll number and name of students who got A grade in at least one course taught by teacher named Ramesh for the above relational database.

The following relations are used to store data about students, courses, enrollment of students in courses and teachers of courses. Attributes for primary key in each relation are marked by ‘*’.

 Students (rollno*, sname, saddr)
 courses (cno*, cname)
 enroll(rollno*, cno*,grade)
 teach(tno*,tname,cao*) 

(cno is course number, cname is course name, tno is teacher number, tname is teacher name, sname is student name, etc.)

For the relational database given above, the following functional dependencies hold:

 rollno → sname,sdaddr      cno → cname
 tno → tname rollno,             cno → grade 

(a) Is the database in 3^rd normal form (3NF)?
(b) If yes, prove that it is in 3 NF. If not, normalize, the relations so that they are in 3 NF (without proving).

(a) How is redundancy reduced in the following models?

 (i) Hierarchical
 (ii) Network
 (iii) Relational 

Write a one line answer in each case.

(b) Suppose we have a database consisting of the following three relations:

 FREQUENTS       (CUSTOMER, HOTEL)
 SERVES          (HOTEL, SNACKS)
 LIKES           (CUSTOMER, SNACKS) 

The first indicates the hotels each customer visits, the second tells which snacks each hotel serves and the last indicates which snacks are liked by each customer. Express the following query in relational algebra: print the hotels that serve a snack that customer Rama likes.

Suppose, a database consists of the following relations:

     SUPPLIER (SCODE, SNAME, CITY)
     PART (PCODE, PNAME, PDESC, CITY)
     PROJECTS (PRCODE, PRNAME, CITY)
     SPRR (SCODE, PCODE, PRCODE, QJY)  

(a) Write SQL programs corresponding to the following queries:
(i) Print PCODE value for parts supplied to any project in DELHI by a supplier in DELHI.
(ii) Print all triples (CITY, PCODE, CITY), such that a supplier in the first city supplies the specified part to a project in the second city, but do not print triples in which the two CITY values are the same.

(b) Write algebraic solutions to the following:
(i) Get SCODE values for suppliers who supply to both projects PR1 and PR2.
(ii) Get PRCODE values for projects supplied by at least one supplier not in the same city.

A table T1 in a relational database has the following rows and columns:

 roll no.	 marks
    1	          10
    2	          20
    3	          30
    4	         Null 

Update T1 set marks = marks + 5
Select avg(marks) from T1 

A relational database contains two tables student and department in which student table has columns roll_no, name and dept_id and department table has columns dept_id and dept_name. The following insert statements were executed successfully to populate the empty tables:

Insert into department values (1, 'Mathematics')
Insert into department values (2, 'Physics')
Insert into student values (l, 'Navin', 1)
Insert into student values (2, 'Mukesh', 2)
Insert into student values (3, 'Gita', 1)  

Select * from student, department

In an inventory management system implemented at a trading corporation, there are several tables designed to hold all the information. Amongst these, the following two tables hold information on which items are supplied by which suppliers, and which warehouse keeps which items along with the stock-level of these items.
Supply = (supplierid, itemcode)
Inventory = (itemcode, warehouse, stocklevel)
For a specific information required by the management, following SQL query has been written

Select distinct STMP.supplierid
From Supply as STMP
Where not unique (Select ITMP.supplierid
                  From Inventory, Supply as ITMP
                  Where STMP.supplierid = ITMP.supplierid
                  And ITMP.itemcode = Inventory.itemcode
                  And Inventory.warehouse = 'Nagpur'); 

A table 'student' with schema (roll, name, hostel, marks), and another table 'hobby' with schema (roll, hobbyname) contains records as shown below:

Table: Student
ROLL	    NAME	HOSTEL	MARKS
1798	Manoj Rathod	  7	 95
2154	Soumic Banerjee	  5	 68
2369	Gumma Reddy	  7	 86
2581	Pradeep Pendse	  6	 92
2643	Suhas Kulkarni	  5	 78
2711	Nitin Kadam	  8	 72
2872	Kiran Vora	  5	 92
2926	Manoj Kunkalikar  5	 94
2959	Hemant Karkhanis  7	 88
3125	Rajesh Doshi	  5	 82 

Table: hobby
ROLL	HOBBYNAME
1798	chess
1798	music
2154	music
2369	swimming
2581	cricket
2643	chess
2643	hockey
2711	volleyball
2872	football
2926	cricket
2959	photography
3125	music
3125	chess 

The following SQL query is executed on the above tables:

select hostel
from student natural join hobby
where marks >= 75 and roll between 2000 and 3000; 

Relations S and H with the same schema as those of these two tables respectively contain the same information as tuples. A new relation S’ is obtained by the following relational algebra operation:

S’ = ∏hostel ((σs.roll = H.roll(σmarks > 75 and roll > 2000 and roll < 3000 (S)) X (H))  

The difference between the number of rows output by the SQL statement and the number of tuples in S’ is

A company maintains records of sales made by its salespersons and pays them commission based on each individual's total sales made in a year. This data is maintained in a table with following schema:
salesinfo = (salespersonid, totalsales, commission)
In a certain year, due to better business results, the company decides to further reward its salespersons by enhancing the commission paid to them as per the following formula:
If commission < = 50000, enhance it by 2% If 50000 < commission < = 100000, enhance it by 4% If commission > 100000, enhance it by 6%
The IT staff has written three different SQL scripts to calculate enhancement for each slab, each of these scripts is to run as a separate transaction as follows:

 T1:	
Update salesinfo
Set commission = commission * 1.02
Where commission < = 50000;
 
 T2:	
Update salesinfo
Set commission = commission * 1.04
Where commission > 50000 and commission is < = 100000;
 
 T3:	
Update salesinfo
Set commission = commission * 1.06
Where commission > 100000;  

Consider a database with three relation instances shown below. The primary keys for the Drivers and Cars relation are did and cid respectively and the records are stored in ascending order of these primary keys as given in the tables. No indexing is available

What is the output of the following SQL query?

select D.dname
from Drivers D
where D.did in (
                 select R.did
                 from Cars C, Reserves R
                 where R.cid = C.cid and C.colour = 'red'
                 intersect
                 select R.did
                 from Cars C, Reserves R
                 where R.cid = C.cid and C.colour = 'green'
                )

Consider a database with three relation instances shown below. The primary keys for the Drivers and Cars relation are did and cid respectively and the records are stored in ascending order of these primary keys as given in the tables. No indexing is available

Let n be the number of comparisons performed when the above SQL query is optimally executed. If linear search is used to locate a tuple in a relation using primary key, then n lies in the range

Consider the following relational schema:

Student (school-id, sch-roll-no, sname, saddress)
School (school-id, sch-name, sch-address, sch-phone)
Enrolment(school-id, sch-roll-no, erollno, examname)
ExamResult(erollno, examname, marks)

What does the following SQL query output?

SELECT  sch-name, COUNT (*)
FROM    School C, Enrolment E, ExamResult R
WHERE   E.school-id = C.school-id
        AND
        E.examname = R.examname AND E.erollno = R.erollno
        AND
        R.marks = 100 AND S.school-id IN (SELECT school-id
                                FROM student
                                GROUP BY school-id
                                HAVING COUNT (*) > 200)
GROUP By school-id

The employee information in a company is stored in the relation

Employee (name, sex, salary, deptName)
Consider the following SQL query
         Select deptName
                    From Employee
                    Where sex = 'M'
                    Group by deptName
                    Having avg (salary) > 
                       (select avg (salary) from Employee)

It returns the names of the department in which

Consider the following relational schema:

  employee(empId, empName, empDept)
  customer(custId, custName, salesRepId, rating)

salesRepId is a foreign key referring to empId of the employee relation. Assume that each employee makes a sale to at least one customer. What does the following query return?

SELECT empName
        FROM employee E
        WHERE NOT EXISTS (SELECT custId
                         FROM customer C
                         WHERE C.salesRepId = E.empId
                         AND C.rating <> `GOOD`); 

Consider the following relations:

Consider the following SQL query.

SELECT S. Student_Name, sum(P.Marks)
     FROM Student S, Performance P
     WHERE S.Roll_No = P.Roll_No
     GROUP BY S.Student_Name

The number of rows that will be returned by the SQL query is _________.

SELECT operation in SQL is equivalent to

Consider the following database table named water_schemes :

The number of tuples returned by the following SQL query is _________.

with total(name, capacity) as
   select district_name, sum(capacity)
   from water_schemes
   group by district_name
with total_avg(capacity) as
   select avg(capacity)
   from total
select name
   from total, total_avg
   where total.capacity ≥ total_avg.capacity

Consider the following database table named top_scorer.

SELECT ta.player FROM top_scorer AS ta
WHERE ta.goals > ALL (SELECT tb.goals
                  FROM top_scorer AS tb
                  WHERE tb.country = 'Spain')
AND ta.goals > ANY (SELECT tc.goals
                  FROM top_scorer AS tc
                  WHERE tc.country = 'Germany')

The number of tuples returned by the above SQL query is _____.

Consider a database that has the relation schema EMP (EmpId, EmpName, and DeptName). An instance of the schema EMP and a SQL query on it are given below.

The output of executing the SQL query is ___________.

Consider the following two tables and four queries in SQL.

Query 1:    SELECT B.isbn, S.copies
            FROM Book B INNER JOIN Stock S
            ON B.isbn = S.isbn;

Query 2:    SELECT B.isbn, S.copies
            FROM Book B LEFT OUTER JOIN Stock S
            ON B.isbn = S.isbn;

Query 3:    SELECT B.isbn, S.copies
            FROM Book B RIGHT OUTER JOIN Stock S
            ON B.isbn = S.isbn;

Query 4:    SELECT B.isbn, S.copies
            FROM Book B FULL OUTER JOIN Stock S
            ON B.isbn = S.isbn;

Which one of the queries above is certain to have an output that is a superset of the outputs of the other three queries?

A relational database contains two tables Student and Performance as shown below:

The primary key of the Student table is Roll_no. For the Performance table, the columns Roll_no. and Subject_code together from the primary key. Consider the SQL query given below:

SELECT S.Student_name, sum (P.Marks)
       FROM Student S, Performance P
       WHERE P.Marks > 84
       GROUP BY S.Student_name;

The number of rows returned by the above SQL query is _____.