50 QUESTIONS AND ANSWERS
ENTITY RELATIONSHIP MODEL
1.An entity that is related with itself is known as…….
(A) Binary relationship
(B) Recursive relationship
(C) Ternary relationship
(D) None of the above
Answer:(B)Recursive relationship
2.A collection of conceptual tools for describing data, relationships, semantics
and constraints is referred to as ……….
(A) Data Model
(B) E-R Model
(C) DBMS
(D) All of the abov
Answer: (A) Data Model
3.Dr.E.F. Codd represented ……. Rules that a database must obey if it has to
be considered truly relational.
(A) 10
(B) 15
(C) 14
(D) 12
Answer:(D) 12
4.In E-R Diagram, weak entity is represented by…….
(A) Rectangle
(B) Square
(C) Double Rectangle
(D) Circle
Answer:(C) Double Rectangle
5.……. is a bottom-up approach in which two lower level entities combine to
form a higher level entity.
(A) Aggregation
(B) Specialization
(C) Generalization
(D) None of the above
Answer:(C) Generalization
6.An entity set that does not have sufficient attributes to form a primary key,
is a ……
(A) Primary entity set
(B) Weak entity set
(C) Strong entity set
(D) None of the above
Answer:(B) Weak entity set
7.Which SQL command delete all the records and does not remove the
structure?
(A) Drop
(B) Insert
(C) Truncate
(D) None of the above
Answer:(C) Truncate
8.Which of the following is a Data Definition Language (DDL) command?
(A) Delete
(B) Insert
(C) Drop
(D) Merge
Answer:(C)Drop
9.In …….. database, data is organized in the form of trees with nodes.
(A) Hierarchical
(B) Relational
(C) Network
(D) None of the above
Answer:(A)Hierarchical
10.Which command is used to retrieve records from one or more table?
(A) Delete
(B) Insert
(C) Drop
(D) Select
Answer:(D) Select
11.Which of the following indicates the maximum number of entities that can
be involved in a relationship?
(A)Minimum cardinality
(B)Maximum cardinality
(C)ERD
(D)Greater Entity Count
Answer:(B)Maximum Cardinality
12.Which type of entity cannot exist in the database unless another type of
entity also exists in the database, but does not require that the identifier of
that other entity be included as part of its own identifier?
(A)Weak entity
(B) Strong entity
(C)ID-dependent entity
(D)ID-independent entity
Answer:(A)Weak entity
13. In a one-to-many relationship, the entity that is on the one side of the
relationship is called a(n) ________ entity.
(A)Parent
(B)Child
(C)Instance
(D)Subtype
Answer:(A)Parent
14.Which type of entity represents an actual occurrence of an associated
generalized entity?
(A)Supertype entity
(B) Subtype entity
(C)Archetype entity
(D)Instance entity
Answer:(D)Instance entity
15.Which of the following indicates the minimum number of entities that
must be involved in a relationship?
(A)Minimum cardinality
B)Maximum cardinalit
(C)ERD
(D)Greater Entity Count (GEC)
Answer: (A)Minimum cardinality
16. Which of the following refers to something that can be identified in the
users' work environment, something that the users want to track?
(A)Entity
(B)Attribute
(C)Identifier
(D)Relationship
Answer:(A)Entity
15. The followings are components odf database except?
(A)Reports
(B)Userdata
(C)Metadata
(D)Indexes
Answer: (A)Reports
16. Entities can be associated with one another in which of the following?
(A)Entity
(B)Attribute
(C)Identifier
(D)Relationship
Answer:(D)Relationship
17. In which of the following is a single-entity instance of one type related to
many entity instances of another type?
(A)One-to-One Relationship
(B)One-to-Many Relationship
(C)Many-to-Many Relationship
(D)Composite Relationship
Answer:(B) One to Many Realtionship
18. Which of the following refers to an entity in which the identifier of one
entity includes the identifier of another entity?
(A)Weak entity
(B)Strong entity
(C)ID-dependent entity
(D)ID-independent entity
Answer:(C)ID-dependent entity
19.Which type of entity is related to two or more associated entities that each
contain specialized attributes that apply to some but not all of the instances of
the entity?
A.Supertype Entity
B.Subtype Entity
C.Archetype Entity
D.Instance Entity
Answer:(A)Supertype Entity
20.A recursive relationship is a relationship between an entity and ________
(A)itself
(B)a subtype entity
(C)an archetype entity
(D)an instance entity
Answer:(A)itself
21. In an object-oriented model, one object can access data of another object
by passing:
(A)Instance variable
(B)Message
(C)Variable
(D)None of these
Answer:(B):Message
22. A view of database that appears to an application program is known as:
(A) Schema
(B)Subschema
(C)virtual table
(D)none of the above
Answer:(B)Subschema
23. An abstraction concept for building composite object from their
component object is called:
(A)Specialization
(B)Normalization
(C)Generalization
(D)Aggregation
Answer:(D)Aggregation
24. A set of objects that share a common structure and a common behavior is
called:
(A)Object
(B)Class
(C)Entity
(D)None of these
Answer:(B)Class
25. Every weak entity set can be converted into a strong entity set by:
(A)using generalization
(B)adding appropriate attributes
(C)using aggregation
(D)none of the above
Answer:(B)adding appropriate attributes
26. The number of entities to which another entity can be associated via a
relationship set is expressed as:
(A) Entity
(B)Cardinality
(C)Schema
(D)Attributes
Answer:(B) Cardinality
27. Relations produced from an E-R model will always be in:
(A) First normal form
(B)Second normal form
(C)Third normal form
(D)Fourth normal form
Answer:(C)Third normal form
28. In ER model the details of the entities are hidden from the user. This
process is called:
(A)Generalization
(B)Specialization
(C)Abstraction
(D)none of these above
Answer:(C)Abstraction
29. The file organization that provides very fast access to any arbitrary
record of a file is:
(A) Ordered file
(B)Unordered file
(C)Hashed file
(D)B-tree
Answer:(C)Hashed file
30. What is not true about a view?
(A) It is a definition of a restricted portion of
the database
(B) It is a security mechanism
(C) It is always updatable like any other table
(D) All are true
Answer:(C)It is always updatable like any other table
31. In a relational database a referential integrity constraint can be specified
with the help of
(A) primary key
(B) foreign key
(C) secondary key
(D) none of the above
Answer:(B)Foreign key
32. A super key is a set of one or more attributes that, taken collectively,
allow us
(A) to identify uniquely an entity in the entity
set
(B) to make the key most powerful for faster
retrieval
(C) to increase effectiveness of database access
(D) none of the above
Answer:(A) to identify uniquely an entity in the entity set
33. 4NF is designed to cope with:
(A) Transitive dependency
(B) Join dependency
(C) Multi valued dependency
(D) None of these
Answer:( C) Multi valued dependency
34. Every Boyee-Codd normal form is in
(A) First normal form
(B) Second normal form
(C) Third normal form
(D) All of the above
Answer:(D)All of the above
35. Which command is used to remove all rows from a table?
(A) Delete
(B) Remove
(C) Truncate
(D) Both [A] and [B]
Answer:(C)Truncate
36. Which of the following is an aggregate function in SQL?
(A) Union
(B) Like
(C) Group By
(D) Max
Answer:(D)Max
37. Which command is used to add a column to an existing table?
(A)Create
(B) Update
(C)Alter
(D)None of these
Answer:(C)Alter
38. A deadlock exists in the system if and only if the wait for graph:
(A) has a cycle in it
(B) has a path from first node to last node
(C) is a tree
(D) none of the above
Answer:(A)has a cycle in it
39. Rollback of transactions is normally used to:
(A) recover from transaction failure
(B) update the transaction
(C) retrieve old records
(D) repeat a transaction
Answer:(A)recover from transaction failure
40. Prevention of access to the database by unauthorized users is referred to
as:
(A) Integrity
(B) Productivity
.(C) Security
(D) Reliability
Answer:(C)Security
41. An ________ is a set of entities of the same type that share the same
properties, or attributes .
(A) Entity set
(B) Attribute set
(C) Relation set
(D) Entity model
Answer:(A) Entity set
42. Entity is a
(A) Object of relation
(B) Present working model
(C) Thing in real world
(D) Model of relation
Answer:(C) Thing in real world
43. The descriptive property possessed by each entity set is _________ .
(A) Entity
(B) Attribute
(C) Relation
(D) Model
Answer:(B) Attribute
44. The function that an entity plays in a relationship is called that entity’s
_____________.
(A) Participation
(B) Position
(C) Role
(D) Instance
Answer:(C) Role
45. The attribute name could be structured as a attribute consisting of first
name, middle initial, and last name . This type of attribute is called
(A) Simple attribute
(B) Composite attribute
(C) Multivalued attribute
(D) Derived attribute
Answer:(B) Composite attribute
46. The attribute AGE is calculated from DATE_OF_BIRTH . The attribute
AGE is
(A) Single valued
(B) Multi valued
(C) Composite
(D) Derived
Answer:(D) Derived
47. Not applicable condition can be represented in relation entry as
(A) NA
(B) 0
(C) NULL
(D) Blank Space
Answer:(C) NULL
48. Which of the following can be a multivalued attribute ?
(A) Phone_number
(B) Name
(C) Date_of_birth
(D) All of the mentioned
Answer:(A) Phone_number
49. Which of the following is a single valued attribute
(A) Register_number
(B) Address
(C) SUBJECT_TAKEN
(D) Reference
Answer:(A) Register_number
50. In a relation between the entities the type and condition of the relation
should be specified . That is called as______attribute
(A) Desciptive
(B) Derived
(C) Recursive
(D) Relative
Answer:(A) Desciptive
