Computer Science – Database Management Systems

Which normal form is considered adequate for relational database design?

The concept of locking can be used to solve the problem of

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, if

A functional dependency of the form X → Y is trivial if

If every non-key attribute is functionally dependent on the primary key, then the relations will be in

The column of a table is referred to as the

Using relational algebra, the query that finds customers who have a balance of over 1000 is

Which of the following queries finds the clients of banker Agassi and the city they live in?

Which of the following tuple relational calculus finds all customers who have a loan amount of more than 1200?

Which of the following Domain relational calculus finds all customers who have a loan amount of over 1200 ?

Given the functional dependencies
X → W ; X → Y : Y → Z and Z → PQ
which of the following does does not hold good ?

What are the potential problems when a DBMS executes multiple transaction concurrently?

The data flow model of an application mainly shows

Consider the set of relations given below and the SQL query that follows:
student: (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?

Which of the following desired features are beyond the capability of relational algebra?

In airline reservation system, the entities are data, flight number, place of departure, destination. type of plane and seats available. The primary key is

For a database relation R (a,b,c,d) where the domains of a,b,c and d include only atomic values, only the following functional dependencies and those that can be inferred from them hold
a → c
b → d
The relation is in

Consider the following relation schema pertaining to a students database.
Student: (rollno, name, address)
Enroll: (rollno, courseno, coursename)
Where the primary keys are shown underlined. The number of tuples in the Student and the Enroll tables are 120 and 8 respectively. What are the maximum and the minimum number of tuples that can be present in (Student * Enroll), Where * denotes natural jaoin?

In an E-R diagram ellipses represent

The set of permitted values for each attribute is called its

In an entity relationship, Y is the dominant entity and x is a subordinate entity. Which of the following is/are incorrect?

The employee information in a company is stored in the relation
Employee: (name, sex, salary, deptName)
Assume name is the primary key. Consider the SOL query
SELECT deptName
FROM Employee
Where SEX = M
GROUP By deptName
HAVING avg(salary) > (SELECT avg(salary) FROM Empolyee)
It returns the names of the departments in which the average salary

A data model is a collection of conceptual tools for describing

Choose the correct statements.

Choose the incorrect statement(s)

Student and courses enrolled, is an example of

Relations produced from an E-R model will always be in

Choose the correct statement.

E-R modeling technique is a

Third normal form is inadequate in situations where the relation

Redundancy is dangerous as it is a potential threat to data

Let R be a relation. Which of the following comments about the relation R are correct?

An attribute of one table matching the primary key of another table, is called as

A primary key if combined with a foreign key creates

Choose the correct statement.

The employee salary should not be greater than RS. 2000. This is

Manager’s salary details are hidden from the employee. This is

The SQL expression
select distinct T.branch_name from branch T. branch S where T.assets > S.assets and S.branch_city = “PONDICHERRY”
finds the names of

A trigger is

Which is the discriminator of the weak entity?

Which is the primary key of the weak entity?

Consider the relation
EMPLOYEE (Emp-no, Emp-name, salary, project-no, due-date)
(Assuming an 1-1 relationship between project and employees)
Project-no is functionally dependent on

In the previous question. which of the following is/are functionally dependent on Emp-name? (Assume no two persons have the same name.)

Let R(a,b,c) and S(d,e,f)be two relations in which d is the foreign key of S that refers to the primary key of R. Consider the following four operations.

Which of the following schemes are used for ensuring atomicity?

If P and Q are predicates and P is the relational algebra expression, then which of the following equivalence are valid?

Generally speaking, for a weak set to be meaningful it must be part of a

If a relation scheme is in BCNF, then it is also in

Consider the following set of functional dependencies on the scheme (A, B, C)
A → BC
B → C
A → B
AB → C
The canonical cover for this set is

Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R, it will