CUET CS Chapter-Understanding Data 

MCQ-Based Questions for CUET Computer Science Chapter-Understanding Data 

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Practice Questions for CUET Computer Science chapter-Understanding Data SET-1

Computer Science - MCQ on Database Concepts

Class XII

Q.1 The number of fundamental operations in relational algebra are

a) four.

b) five.

c) six.

d) seven.

Answer:

(c)

Explanation: There are six fundamental operations: select, project, rename, cartesian product, union and set-difference.

Q.2 The binary operation in relational algebra among the following is

a) select.

b) project.

c) rename.

d) union.

Answer:

(d)

Explanation: Union is the binary operation and others are unary operations.

Q.3 DDL stands for

a) Definition Data Language.

b) Data Definition Language.

c) Data Degree Language.

d) Database Degree Language.

Answer:

(b)

Explanation: A Data Definition Language (DDL) is a computer language for defining data structures.

Q.4 The number of data models available are

a) two.

b) three.

c) four.

d) five.

Answer:

(b)

Explanation: There are three data models available: relational, hierarchical and network data model.

Q.5 The advantage of hierarchical data model is

a) reduction of data dependency.

b) addition of node.

c) complexity.

d) machine performance.

Answer:

(b)

Explanation: The main advantage of the hierarchical data model is that, we can easily attach any child node to any parent node directly.

Q.6 The main disadvantage of hierarchical data model is

a) reduction of data dependency.

b) machine performance.

c) complexity.

d) flexibility.

Answer:

(a)

Explanation: The main disadvantage of this model is reduction of data dependency and if we delete parent node, child node will automatically get deleted.

Q.7 The disadvantage of relational model is

a) reduction of data dependency.

b) machine performance.

c) complexity.

d) flexibility.

Answer:

(b)

Explanation: The main disadvantage of relational model is machine performance. If the number of tables increases, the response time gets increased.

Q.8 A set of entities of some type constitutes an

a) entity

b) attributes

c) entity set.

d) relationship.

Answer:

(c)

Explanation: A set of entities of some type, i.e., which share common properties constitutes an entity set.

Q.9 An association among several entities, is known as

a) entity

b) attributes

c) entity set.

d) relationship.

Answer:

(d)

Explanation: A relationship is an association among several entities. For example, a teacher teaches a student. Here teacher and student are entities and teaches is the relationship between them.

Q.10 An attribute in a table, which is the key attribute in some other table, is known as

a) primary key.

b) composie key.

c) alternate key.

d) foreign key.

Answer:

(d)

Explanation: A foreign key is a field (or fields) that points to the primary key of another table. The purpose of the foreign key is to ensure referential integrity of the data.

Q.11 When multiple fields are used as a primary key, they are called a

a) primary key.

b) composite key.

c) foreign key.

d) composite key.

Answer:

(b)

Explanation: Any key or minimum set of keys that could be a primary key is called a candidate key.

Q.12 Candidate keys which are not chosen as the primary key are known as

a) primary key.

b) composite key.

c) alternate key.

d) foreign key.

Answer:

(c)

Explanation: In the context of relational databases, an alternate key (or secondary key) is any candidate key which is not selected to be the primary key (PK).

Q.13 The number of tuples in the relation is called its

a) degree.

b) cardinality.

c) attributes.

d) entity.

Answer:

(b)

Explanation: The term cardinality refers to the number of cardinal (basic) members in a set. Cardinality can be a finite (a non-negative integer) or infinite.

Q.14 The rows of the table are called

a) attributes.

b) tuples.

c) cardinality.

d) entity.

Answer:

(b)

Explanation: In mathematics, a tuple is a sequence (or ordered list) of finite length. An n-tuple is a tuple with n elements.

Q.15 The columns of the table are called

a) attributes.

b) tuples.

c) cardinality.

d) entity.

Answer:

(a)

Explanation: A factor of an object or other kind of entity is known as attributes.

Q.16 The data stored at different levels should not affect each other when they get changed. It refers to

a) data integrity.

b) functional dependency.

c) referential integrity.

d) data independence.

Answer:

(d)

Explanation: Data independence is the type of data transparency that matters for a centralized DBMS. It refers to the immunity of user applications to make changes in the definition and organization of data, and vice-versa.

Q.17 The way a particular application views the data from the database is called

a) schema.

b) preschema.

c) post-schema.

d) subschema.

Answer:

(d)

Explanation: A subschema suggests a schema that is subordinate to some other schema.

Q.18 The smallest unit of database record is

a) tuple.

b) attribute.

c) field.

d) degree.

Answer:

(c)

Explanation: In computer science, data that has several parts can be divided into fields. For example, a computer may represent today's date as three distinct fields: the day, the month and the year.

Q.19 The disadvantage of file management system is

a) reduced redundancy.

b) no data sharing.

c) secured data.

d) standardized data.

Answer:

(b)

Explanation: In file management system, it is not possible to share the data. Due to non-sharing of data, redundancy of data is possible.

Q.20 The advantage of database management system is

a) reduced redundancy.

b) non-sharing of data.

c) inconsistency.

d) non-standardized data.

Answer:

(a)

Explanation: : In database management system, it is possible to share the data. Due to sharing of data, redundancy of data is reduced.

Q.21 The logical data structure with a one-to-many relationship, is

a) queue.

b) linked list.

c) tree.

d) stack.

Answer:

(c)

Explanation: In tree, one node (parent node) is connected to many other nodes (child nodes), thus a one-to-many relationship.

Q.22 The data model which is suitable for one-to-many relationship, is

a) relational.

b) network.

c) hierarchical.

d) conceptual.

Answer:

(c)

Explanation: Hierarchical data model is in the form of a tree. In tree, one node (parent node) is connected to many other nodes (child nodes), thus a one-to-many relationship.

Q.23 When both the relations are of the same degree and the domain of the attributes of both the relation is same, it is known as

a) intersection compatibility.

b) projection compatibility.

c) union compatibility.

d) selection compatibility.

Answer:

(c)

Explanation: The union compatibility is defined as such:

the two relations have the same degree n (number of attributes) ,

and (2 domain (Ai)= domain (Bi) for 1=<i<=n, where domain stands for

data type.

Q.24 A tuple is equivalent to

a) relation.

b) record.

c) degree.

d) operator.

Answer:

(b)

Explanation: The rows of the table are called tuples, which are equivalent to a record.

Q.25 The database model which are represented in the form of tables is

a) relational data model.

b) network data model.

c) hierarchical data model.

d) tree data model.

Answer:

(a)

Explanation: The relational model for database management is a database model based on first-order predicate logic, first formulated and proposed in 1969 by E.F. Codd.The relational data model uses the concept of tables.

Q.26 Data items grouped together for storage purposes is called a

a) table.

b) relation.

c) record.

d) tree.

Answer:

(c)

Explanation: An ordered set of fields, usually stored contiguously is known as a record.