Question on Concepts Of Keys and Integrity Constraints | DBMS | MCQ

Question on Concepts ER Models| DBMS | MCQ
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Q1. Which of the following defines the structure and organization of a
database?
a) Data manipulation language
b) Database schema
c) Data definition language
d) Database instance

View Answer
b

Q2. Which of the following schema is used to describe the internal
organization of a database on disk?
a) Physical schema
b) Logical schema
c) External schema
d) Conceptual schema

View Answer
a

Q3. Which one is correct w.r.t. RDBMS?
a) primary key ⊆ super key ⊆ candidate key
b) primary key ⊆ candidate key ⊆ super key
c) super key ⊆ candidate key ⊆ primary key
d) super key ⊆ primary key ⊆ candidate key

View Answer
b

Q4. 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 R and S.
I) Insert into R
II) Insert into S
III) Delete from R
IV) Delete from S

Which of the following can cause a violation of the referential integrity
constraint above?

a) Both I and IV
b) Both II and III
c) All of these
d) None of these
View Answer

b

Q5. Which of the following is a schema used to define the structure and
organization of a database?
a) Physical schema
b) Logical schema
c) Conceptual schema
d) External schema

View Answer
c

Q6. 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:

I) {B} II) {B, C}) III) {A, D} IV) {C, D}

a) I and III
b) III and IV
c) II only
d) I only

View Answer
c

Q7. R(ABCD) four attributes in R table. If A and B are two candidate keys
then find the super keys

a)  8
b) 16
c)  10
d) 12

View Answer
d

Q8. Which one of the following is a set of one or more attributes taken
collectively to uniquely identify a record?
(a) Candidate key
(b) Sub key
(c) Super key
(d) Foreign key

View Answer
c

Q9. The _______ is the one in which the primary key of one relation is
used as a normal attribute in another relation.
a) Referential relation
b) Referencing relation
c) Referenced relation
d) Referred relation

View Answer
c

Q10. Which of the following schema is closest to the way users perceive the
data?
a) Physical schema
b) Logical schema
c) External schema
d) Conceptual schema

View Answer
c

Q11. An attribute in a relation is a foreign key if the ____ key from one
relation is used as an attribute in that relation.

a) Candidate
b) Primary
c) Super
d) Alternative

View Answer
b

Q12. Which of the following is NOT a component of a database schema?
a) Tables and their relationships
b) Views
c) Indexes
d) User

View Answer
d

Q13. Which of the following statements is true about composite primary
keys?
a) A composite primary key is composed of multiple columns that
individually serve as primary keys
b) A composite primary key is composed of a single column that contains
multiple values
c) A composite primary key is composed of multiple columns that, when
combined, uniquely identify a row in a table
d) A composite primary key is not allowed in a relational database

View Answer
c

Q14. The ability to change the conceptual schema without affecting the
external schemas or application programs is known as _____
a) Program Data Independence
b) Physical Data Independence
c) Logical Data Independence
d) Data Abstraction

View Answer
c

Q15. R(ABCDE) five attributes in the R table. If ‘AB’ and ‘CD’ are two
candidate keys then find all the super keys?
a) 12
b) 14
c) 16
d) 18

View Answer
b
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