MOST IMPORTANT MCQ'S FOR DBMS PAPER FOR MID TERM (All the Best)
Relational Model
1. A relational database consists of a collection of
a) Tables
b) Fields
c) Records
d) Keys
2. A ________ in a table represents a relationship among a set of values.
a) Column
b) Key
c) Row
d) Entry
3. The term _______ is used to refer to a row.
a) Attribute
b) Tuple
c) Field
d) Instance
4. The term attribute refers to a ___________ of a table.
a) Record
b) Column
c) Tuple
d) Key
5. For each attribute of a relation, there is a set of permitted values, called the ________ of that attribute.
a) Domain
b) Relation
c) Set
d) Schema
6. Database __________ which is the logical design of the database, and the database _______ which is a snapshot of the data in the database at a given instant in time.
a) Instance, Schema
b) Relation, Schema
c) Relation, Domain
d) Schema, Instance
7. Course(course_id,sec_id,semester)
Here the course_id,sec_id and semester are __________ and course is a _________
a) Relations, Attribute
b) Attributes, Relation
c) Tuple, Relation
d) Tuple, Attributes
8. Department (dept name, building, budget) and Employee (employee_id, name, dept name, salary)
Here the dept_name attribute appears in both the relations. Here using common attributes in relation schema is one way of relating ___________ relations.
a) Attributes of common
b) Tuple of common
c) Tuple of distinct
d) Attributes of distinct
9. A domain is atomic if elements of the domain are considered to be ____________ units.
a) Different
b) Indivisbile
c) Constant
d) Divisible
10. The tuples of the relations can be of ________ order.
a) Any
b) Same
c) Sorted
d) Constant
11. 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
12. Consider attributes ID, CITY and NAME. Which one of this can be considered as a super key?
a) NAME
b) ID
c) CITY
d) CITY, ID
13. The subset of a super key is a candidate key under what condition?
a) No proper subset is a super key
b) All subsets are super keys
c) Subset is a super key
d) Each subset is a super key
14. A _____ is a property of the entire relation, rather than of the individual tuples in which each tuple is unique.
a) Rows
b) Key
c) Attribute
d) Fields
15. Which one of the following attribute can be taken as a primary key?
a) Name
b) Street
c) Id
d) Department
16. Which one of the following cannot be taken as a primary key?
a) Id
b) Register number
c) Dept_id
d) Street
17. 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) Sub
18. The relation with the attribute which is the primary key is referenced in another relation. The relation which has the attribute as a primary key is called
a) Referential relation
b) Referencing relation
c) Referenced relation
d) Referred relation
19. 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
20. A _________ integrity constraint requires that the values appearing in specified attributes of any tuple in the referencing relation also appear in specified attributes of at least one tuple in the referenced relation.
a) Referential
b) Referencing
c) Specific
d) Primary
21. Using which language can a user request information from a database?
a) Query
b) Relational
c) Structural
d) Compiler
22. Student(ID, name, dept name, tot_cred)
In this query which attributes form the primary key?
a) Name
b) Dept
c) Tot_cred
d) ID
23. Which one of the following is a procedural language?
a) Domain relational calculus
b) Tuple relational calculus
c) Relational algebra
d) Query language
24. The_____ operation allows the combining of two relations by merging pairs of tuples, one from each relation, into a single tuple.
a) Select
b) Join
c) Union
d) Intersection
25. The result which operation contains all pairs of tuples from the two relations, regardless of whether their attribute values match.
a) Join
b) Cartesian product
c) Intersection
d) Set difference
26. The _______operation performs a set union of two “similarly structured” tables
a) Union
b) Join
c) Product
d) Intersect
27. The most commonly used operation in relational algebra for projecting a set of tuple from a relation is
a) Join
b) Projection
c) Select
d) Union
28. The _______ operator takes the results of two queries and returns only rows that appear in both result sets.
a) Union
b) Intersect
c) Difference
d) Projection
29. A ________ is a pictorial depiction of the schema of a database that shows the relations in the database, their attributes, and primary keys and foreign keys.
a) Schema diagram
b) Relational algebra
c) Database diagram
d) Schema flow
30. The _________ provides a set of operations that take one or more relations as input and return a relation as an output.
a) Schematic representation
b) Relational algebra
c) Scheme diagram
d) Relation flow
Relational Algebra
1. Relational Algebra is a __________ query language that takes two relations as input and produces another relation as an output of the query.
a) Relational
b) Structural
c) Procedural
d) Fundamental
2. Which of the following is a fundamental operation in relational algebra?
a) Set intersection
b) Natural join
c) Assignment
d) None of the mentioned
3. Which of the following is used to denote the selection operation in relational algebra?
a) Pi
b) Sigma
c) Lambda
d) Omega
4. For select operation the ________ appear in the subscript and the ___________ argument appears in the paranthesis after the sigma.
a) Predicates, relation
b) Relation, Predicates
c) Operation, Predicates
d) Relation, Operation
5. The ___________ operation, denoted by −, allows us to find tuples that are in one relation but are not in another.
a) Union
b) Set-difference
c) Difference
d) Intersection
6. Which is a unary operation:
a) Selection operation
b) Primitive operation
c) Projection operation
d) Generalized selection
7. Which is a join condition contains an equality operator:
a) Equijoins
b) Cartesian
c) Natural
d) Left
8. In precedence of set operators, the expression is evaluated from
a) Left to left
b) Left to right
c) Right to left
d) From user specification
9. Which of the following is not outer join?
a) Left outer join
b) Right outer join
c) Full outer join
d) All of the mentioned
10. The assignment operator is denoted by
a) ->
b) <-
c) =
d) ==
Normalization and Dependencies
1. In the __________ normal form, a composite attribute is converted to individual attributes.
a) First
b) Second
c) Third
d) Fourth
2. A table on the many side of a one to many or many to many relationship must:
a) Be in Second Normal Form (2NF)
b) Be in Third Normal Form (3NF)
c) Have a single attribute key
d) Have a composite key
3. Tables in second normal form (2NF):
a) Eliminate all hidden dependencies
b) Eliminate the possibility of a insertion anomalies
c) Have a composite key
d) Have all non key fields depend on the whole primary key
4. Which-one of the following statements about normal forms is FALSE?
a) BCNF is stricter than 3 NF
b) Lossless, dependency -preserving decomposition into 3 NF is always possible
c) Loss less, dependency – preserving decomposition into BCNF is always possible
d) Any relation with two attributes is BCNF
5. Functional Dependencies are the types of constraints that are based on______
a) Key
b) Key revisited
c) Superset key
d) None of the mentioned
6. Which is a bottom-up approach to database design that design by examining the relationship between attributes:
a) Functional dependency
b) Database modeling
c) Normalization
d) Decomposition
7. Which forms simplifies and ensures that there are minimal data aggregates and repetitive groups:
a) 1NF
b) 2NF
c) 3NF
d) All of the mentioned
8. Which forms has a relation that possesses data about an individual entity:
a) 2NF
b) 3NF
c) 4NF
d) 5NF
9. Which forms are based on the concept of functional dependency:
a) 1NF
b) 2NF
c) 3NF
d) 4NF
10. Empdt1(empcode, name, street, city, stste, pincode)
For any pincode, there is only one city and state. Also, for given street, city and state, there is just one pincode. In normalization terms, empdt1 is a relation in
a) 1 NF only
b) 2 NF and hence also in 1 NF
c) 3NF and hence also in 2NF and 1NF
d) BCNF and hence also in 3NF, 2NF and 1NF
11. We can use the following three rules to find logically implied functional dependencies. This collection of rules is called
a) Axioms
b) Armstrong’s axioms
c) Armstrong
d) Closure
12. Which of the following is not Armstrong’s Axiom?
a) Reflexivity rule
b) Transitivity rule
c) Pseudotransitivity rule
d) Augmentation rule
13. The relation employee(ID, name, street, Credit, street, city, salary) is decomposed into
employee1 (ID, name)
employee2 (name, street, city, salary)
This type of decomposition is called
a) Lossless decomposition
b) Lossless-join decomposition
c) All of the mentioned
d) None of the mentioned
14. Inst_dept (ID, name, salary, dept name, building, budget) is decomposed into
instructor (ID, name, dept name, salary)
department (dept name, building, budget)
This comes under
a) Lossy-join decomposition
b) Lossy decomposition
c) Lossless-join decomposition
d) Both Lossy and Lossy-join decomposition
15. There are two functional dependencies with the same set of attributes on the left side of the arrow:
A->BC
A->B
This can be combined as
a) A->BC
b) A->B
c) B->C
d) None of the mentioned
16. Consider a relation R(A,B,C,D,E) with the following functional dependencies: DE
ABC -> DE
D -> AB
The number of superkeys of R is:
a) 2
b) 7
c) 10
d) 12
17. Suppose relation R(A,B) currently has tuples {(1,2), (1,3), (3,4)} and relation S(B,C) currently has {(2,5), (4,6), (7,8)}. Then the number of tuples in the result of the SQL query:
select * from R Natural Outer join S;
a) 2
b) 4
c) 6
d) None of the mentioned
18. Suppose now that R(A,B) and S(A,B) are two relations with r and s tuples, respectively (again, not necessarily distinct). If m is the number of (not necessarily distinct) tuples in the result of the SQL query: R intersect S
Then which of the following is the most restrictive, correct condition on the value of m?
a) m = min(r,s)
b) 0 <= m <= r + s
c) min(r,s) <= m <= max(r,s)
d) 0 <= m <= min(r,s)
19. Suppose relation R(A,B,C,D,E) has the following functional dependencies:
A -> B
B -> C
BC -> A
A -> D
E -> A
D -> E
20. Which of the following is not a key?
a) A
b) E
c) B, C
d) D
21. A relation is in ____________ if an attribute of a composite key is dependent on an attribute of other composite key.
a) 2NF
b) 3NF
c) BCNF
d) 1NF
22. What are the desirable properties of a decomposition
a) Partition constraint
b) Dependency preservation
c) Redundancy
d) Security
23. R (A,B,C,D) is a relation. Which of the following does not have a lossless join dependency preserving BCNF decomposition?
a) A->B, B->CD
b) A->B, B->C, C->D
c) AB->C, C->AD
d) A->BCD
24. The algorithm that takes a set of dependencies and adds one schema at a time, instead of decomposing the initial schema repeatedly is
a) BCNF algorithm
b) 2NF algorithm
c) 3NF synthesis algorithm
d) 1NF algorithm
25. The functional dependency can be tested easily on the materialized view, using the constraints ____________.
a) Primary key
b) Null
c) Unique
d) Both Null and Unique
26. Which normal form is considered adequate for normal relational database design?
a) 2NF
b) 5NF
c) 4NF
d) 3NF
27. Relation R with an associated set of functional dependencies, F, is decomposed into BCNF. The redundancy (arising out of functional dependencies) in the resulting set of relations is
a) Zero
b) More than zero but less than that of an equivalent 3NF decomposition
c) Proportional to the size of F+
d) Indeterminate
28. A table has fields F1, F2, F3, F4, and F5, with the following functional dependencies:
F1 -> F3
F2 -> F4
( F1, F2 ) -> F5
in terms of normalization, this table is in
a) 1NF
b) 2NF
c) 3NF
d) None of the mentioned
29. Let R(A,B,C,D,E,P,G) be a relational schema in which the following FDs are known to hold:
AB -> CD
DE -> P
C -> E
P -> C
B -> G
The relation schema R is
a) in BCNF
b) in 3NF, but not in BCNF
c) in 2NF, but not in 3NF
d) not in 2NF
30. The normal form which satisfies multivalued dependencies and which is in BCNF is
a) 4 NF
b) 3 NF
c) 2 NF
d) All of the mentioned
31. Which of the following is a tuple-generating dependencies?
a) Functional dependency
b) Equality-generating dependencies
c) Multivalued dependencies
d) Non-functional dependency
32. The main task carried out in the __________ is to remove repeating attributes to separate tables.
a) First Normal Form
b) Second Normal Form
c) Third Normal Form
d) Fourth Normal Form
33. Which of the normal form is based on multivalued dependencies?
a) First
b) Second
c) Third
d) Fourth
34. Which forms has a relation that possesses data about an individual entity?
a) 2NF
b) 3NF
c) 4NF
d) 5NF
35. If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from one of the following sources.
a) A many-to-many relationship set
b) A multivalued attribute of an entity set
c) A one-to-many relationship set
d) Both A many-to-many relationship set and A multivalued attribute of an entity set
36. Which of the following has each related entity set has its own schema and there is an additional schema for the relationship set?
a) A many-to-many relationship set
b) A multivalued attribute of an entity set
c) A one-to-many relationship set
d) None of the mentioned
37. In which of the following, a separate schema is created consisting of that attribute and the primary key of the entity set.
a) A many-to-many relationship set
b) A multivalued attribute of an entity set
c) A one-to-many relationship set
d) None of the mentioned
38. Fifth Normal form is concerned with
a) Functional dependency
b) Multivalued dependency
c) Join dependency
d) Domain-key
39. In 2NF
a) No functional dependencies (FDs) exist
b) No multivalued dependencies (MVDs) exist
c) No partial FDs exist
d) No partial MVDs exist
40. _____________ can help us detect poor E-R design.
a) Database Design Process
b) E-R Design Process
c) Relational scheme
d) Functional dependencies
41. If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from one of the following sources.
a) A many-to-many relationship set
b) A multivalued attribute of an entity set
c) A one-to-many relationship set
d) Both A many-to-many relationship set and A multivalued attribute of an entity set
42. Which of the following has each related entity set has its own schema and there is an additional schema for the relationship set.
a) A many-to-many relationship set
b) A multivalued attribute of an entity set
c) A one-to-many relationship set
d) All of the mentioned
43. In which of the following, a separate schema is created consisting of that attribute and the primary key of the entity set.
a) A many-to-many relationship set
b) A multivalued attribute of an entity set
c) A one-to-many relationship set
d) All of the mentioned
44. Suppose the user finds the usage of room number and phone number in a relational schema there is confusion.This is reduced by
a) Unique-role assumption
b) Unique-key assignment
c) Role intergral assignment
d) None of the mentioned
45. What is the best way to represent the attributes in a large database?
a) Relational-and
b) Concatenation
c) Dot representation
d) All of the mentioned
46. Designers use which of the following to tune the performance of systems to support time-critical operations?
a) Denormalization
b) Redundant optimization
c) Optimization
d) Realization
47. In the schema (dept name, size) we have relations total inst 2007, total inst 2008. Which dependency have lead to this relation ?
a) Dept name, year->size
b) Year->size
c) Dept name->size
d) Size->year
48. Relation dept year(dept name, total inst 2007, total inst 2008, total inst 2009). Here the only functional dependencies are from dept name to the other attributes. This relation is in
a) Fourth NF
b) BCNF
c) Third NF
d) Second NF
49. Thus a _______ of course data gives the values of all attributes, such as title and department, of all courses at a particular point in time.
a) Instance
b) Snapshot
c) Both Instance and Snapshot
d) All of the mentioned
50. Representations such as the in the dept year relation, with one column for each value of an attribute, are called _______ they are widely used in spreadsheets and reports and in data analysis tools.
a) Cross-tabs
b) Snapshot
c) Both Cross-tabs and Snapshot
d) All of the mentioned
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