Q. Consider the following relational schemas for a library database: 
Book (Title, Author, Catalog_no, Publisher, Year, Price) 
Collection (Title, Author, with the following dependencies :

I. Title, Author —> Catalog_no
II. Catalog_no —> Title, Author, Publisher, Year
III. Publisher, Title, Year —> Price
Assume (Author, Title) is the key for both schemas. Which one of the following is true ?

View solution

Q. Specialization Lattice stands for

View solution

Q.
Match the following with respect to the jump statements

List-I List-II

a. Timeout ordering protocol i. Wait for graph

b. Deadlock prevention ii. Roll back

c. Deadlock detection iii. Wait-die scheme

d. Deadlock recovery iv. Thomas Write Rule

Codes:
a b c d

View solution

Q. Consider the schema

R = {S,T, U,V}

and the dependencies

S →T, T → U, U → V and V → S

If   R   =   (R1  and   R2)   be   a decomposition such that R1 ∩ R2 = Ф

then the decomposition is

View solution

Q. Which of the following concurrency protocol ensures both conflict serializability deadlock:
I. 2-phase locking 
II. Time phase ordering 

View solution

Q. The "part-whole", or "a-part-of", relationship in which objects representing the components of something associated with an object representing the entire assembly is called as

View solution

Q. If h is chosen from a universal collection of hash functions and is used to hash n keys into a table of size m, where n ≤ m, the expected number of collisions involving a particular key K is

View solution

Q. In RDBMS, the constraint that no key attribute (column) may be NULL is referred to as:

View solution

Q. Which of the following statement(s) is/are FALSE in the context of Relational DBMS ? I. Views in a database system are important because they help with access control by allowing users to see only a particular subset of the data in the database. II. E-R diagrams are useful to logically model concepts. III. An update anomaly is when it is not possible to store information unless some other, unrelated information is stored as well. IV. SQL is a procedural language.

View solution

Q. In a relational database model, NULL values can be used for all but which one of the following?

View solution

Q. Consider the following two commands C1 and C2 on the relation R from an SQL database:
C1: drop table R;
C2: delete from R;
Which of the following statements is TRUE?
I. Both C1 and C2 delete the schema for R.
II. C2 retains relation R, but deletes all tuples in R.
III. C1 deletes not only all tuples of R, but also the schema for R.

View solution

Q. Consider the following database table having A, B, C and D as its four attributes and four possible candidate keys (I, II, III and IV) for this table:
A B C D
a1 b1 c1 d1
a2 b3 c3 d1
a1 b2 c1 d2

I: {B} II: {B, C} III: {A, D} IV: {C, D}
If different symbols stand for different values in the table (e.g., d1 is definitely not equal to d2), then which of the above could not be the candidate key for the database table?

View solution

Q. An attribute A of datatype varchar(20) has value 'Ram' and the attribute B of datatype char(20) has value 'Sita' in oracle. The attribute A has .......... memory spaces and B has .......... memory spaces.

View solution

Q. Integrity constraints ensure that changes made to the database by authorized users do not result into loss of data consistency. Which of the following statement(s) is (are) true w.r.t. the examples of integrity constraints?

(A) An instructor Id. No. cannot be null, provided Instructor Id. No. being primary key.
(B) No two citizens have same Adhar-Id.
(C) Budget of a company must be zero.

View solution

Q. Let M and N be two entities in an E-R diagram with simple single valued attributes. R1 and R2 are two relationships between M and N, whereas
R1 is one-to-many and R2 is many-to-many.
The minimum number of tables required to represent M, N, R1 and R2 in the relational model are ..........

View solution

Q. Consider a schema R(MNPQ) and functional dependencies M→N, P→Q. Then the decomposition of R into R1(MN) and R2(PQ) is _______

View solution

Q. If h is chosen from a universal collection of hash functions and is used to hash n keys into a table of size m, where n?m, the expected number of collisions involving a particular key x is less than ...................

View solution

Q. Which one is correct w.r.t. RDBMS?

View solution

Q. Let pk(R) denotes primary key of relation R. A many-to-one relationship that exists between two relations R1 and R2 can be expressed as follows:

View solution

Q. 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 are:
A→C
B→D
The relation R is in ................

View solution