DBMS MCQ'S 1
1. A relational database consists of a collection of
a) Tables
b) Fields
c) Records
d) Keys
View Answer
Answer: a
Explanation: Fields are the column of the relation or tables. Records are each row in a relation.
Keys are the constraints in a relation.
advertisement
2. A ________ in a table represents a relationship among a set of values.
a) Column
b) Key
c) Row
d) Entry
View Answer
Answer: c
Explanation: Column has only one set of values. Keys are constraints and row is one whole set
of attributes. Entry is just a piece of data.
3. The term _______ is used to refer to a row.
a) Attribute
b) Tuple
c) Field
d) Instance
View Answer
Answer: b
Explanation: Tuple is one entry of the relation with several attributes which are fields.
4. The term attribute refers to a ___________ of a table.
a) Record
b) Column
c) Tuple
d) Key
View Answer
Answer: b
Explanation: Attribute is a specific domain in the relation which has entries of all tuples.
advertisement
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
View Answer
Answer: a
Explanation: The values of the attribute should be present in the domain. Domain is a set of
values permitted.
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
View Answer
Answer: d
Explanation: Instance is an instance of time and schema is a representation.
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
View Answer
Answer: b
Explanation: The relation course has a set of attributes course_id,sec_id,semester .
advertisement
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
View Answer
Answer: c
Explanation: Here the relations are connected by the common attributes.
9. A domain is atomic if elements of the domain are considered to be ____________ units.
a) Different
b) Indivisbile
c) Constant
d) Divisible
View Answer
Answer: b
Explanation: None.
10. The tuples of the relations can be of ________ order.
a) Any
b) Same
c) Sorted
d) Constant
View Answer
Answer: a
Explanation: The values only count. The order of the tuples does not matter
1. 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
Answer: c
Explanation: Super key is the superset of all the keys in a relation.
advertisement
2. 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
View Answer
Answer: b
Explanation: Here the id is the only attribute which can be taken as a key. Other attributes are
not uniquely identified.
3. 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
View Answer
Answer: a
Explanation: The subset of a set cannot be the same set. Candidate key is a set from a super key
which cannot be the whole of the super set.
4. 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
View Answer
Answer: b
Explanation: Key is the constraint which specifies uniqueness.
advertisement
5. Which one of the following attribute can be taken as a primary key?
a) Name
b) Street
c) Id
d) Department
View Answer
Answer: c
Explanation: The attributes name, street and department can repeat for some tuples. But the id
attribute has to be unique. So it forms a primary key.
6. Which one of the following cannot be taken as a primary key?
a) Id
b) Register number
c) Dept_id
d) Street
View Answer
Answer: d
Explanation: Street is the only attribute which can occur more than once.
7. 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
View Answer
Answer: b
Explanation: The primary key has to be referred in the other relation to form a foreign key in
that relation.
advertisement
8. 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
View Answer
Answer: c
Explanation: None.
9. 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
Answer: c
Explanation: None.
10. 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
View Answer
Answer: a
Explanation: A relation, say r1, may include among its attributes the primary key of another
relation, say r2. This attribute is called a foreign key from r1, referencing r2. The relation r1 is
also called the referencing relation of the foreign key dependency, and r2 is called the referenced
relation of the foreign key.
1. Using which language can a user request information from a database?
a) Query
b) Relational
c) Structural
d) Compiler
View Answer
Answer: a
Explanation: Query language is a method through which the database entries can be accessed.
advertisement
2. 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
View Answer
Answer: d
Explanation: The attributes name, dept and tot_cred can have same values unlike ID.
3. Which one of the following is a procedural language?
a) Domain relational calculus
b) Tuple relational calculus
c) Relational algebra
d) Query language
View Answer
Answer: c
Explanation: Domain and Tuple relational calculus are non-procedural language. Query
language is a method through which database entries can be accessed.
4. 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
View Answer
Answer: b
Explanation: Join finds the common tuple in the relations and combines it.
advertisement
5. 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
View Answer
Answer: b
Explanation: Cartesian product is the multiplication of all the values in the attributes.
6. The _______operation performs a set union of two “similarly structured” tables
a) Union
b) Join
c) Product
d) Intersect
View Answer
Answer: a
Explanation: Union just combines all the values of relations of same attributes.
7. 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
View Answer
Answer: c
Explanation: Select is used to view the tuples of the relation with or without some constraints.
advertisement
8. 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
View Answer
Answer: b
Explanation: The union operator gives the result which is the union of two queries and
difference is the one where query which is not a part of second query.
9. 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
View Answer
Answer: a
Explanation: None.
10. 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
View Answer
Answer: b
Explanation: None
1. Given the evolution of DBMSs, business data is now:
a. Stored in main memory and stays resident there even after the application that uses it terminates.
b. Stored only if it is relevant to business decisions.
c. Stored indefinitely in case it's needed since storing it is much cheaper now.
d. None of the above.
Answer: (b).Stored only if it is relevant to business decisions.
2. Which of the following is not true of a DBMS?
a. It provides efficient storage and retrieval of data.
b. It has evolved over the years into a fairly simple set of tools that are relatively easy to master.
c. Marketplace demands and product innovation have led to the development of a broad range of features.
d. None of the above.
Answer: (b).It has evolved over the years into a fairly simple set of tools that are relatively easy to master.
3. Nonprocedural access to a database:
a. Can provide a dramatic improvement in software productivity.
b. Allows a user to submit queries to a database without having to know how the data will be retrieved.
c. Is supported by more than one tool in most DBMSs.
d. All of the above.
Answer: (d).All of the above.
4. Which of the following statements is not true of a desktop DBMS?
a. They usually run on personal computers or small servers.
b. They have a much lower cost than other DBMSs.
c. Although useful for processing ad hoc queries, they cannot perform transaction processing.
d. They usually support databases used by work teams and small businesses.
Answer: (c).Although useful for processing ad hoc queries, they cannot perform transaction processing.
5. In the evolution of database technology, second-generation products are considered to be the first true DBMSs because:
a. They were "navigational", i.e. the programmer had to write code to navigate through a network of linked records.
b. Of their foundation on mathematical relations and associated operators.
c. They supported sequential and random searching.
d. They could manage multiple entities and relationships.
Answer: (d).They could manage multiple entities and relationships.
6. In the evolution of database technology, third-generation products supplanted second-generation systems because:
a. Nonprocedural database access was an improvement over navigational access.
b. IBM supported the CODASYL standard of database definition and manipulation.
c. Nonprocedural languages were still not very efficient.
d. All of the above.
Answer: (a).Nonprocedural database access was an improvement over navigational access.
7. Which statement is not true of the Three Schema Architecture?
a. It is an official standard of the American Standards Institute (ANSI).
b. It is an architecture for compartmentalizing database descriptions.
c. Its details have been widely adopted in third- and fourth-generation DBMSs.
d. None of the above.
Answer: (c).Its details have been widely adopted in third- and fourth-generation DBMSs.
8. Which of the following statements is not true of information resource management?
a. It is very different and much more challenging than managing the other physical resources of an organization.
b. Its goal is to use information technology as a tool for processing, distributing, and integrating information throughout an organization.
c. Its emergence has created new management responsibilities.
d. None of the above.
Answer: (a).It is very different and much more challenging than managing the other physical resources of an organization.
9. A Database Management System (DBMS) is
a. Collection of interrelated data
b. Collection of programs to access data
c. Collection of data describing one particular enterprise
d. All of the above
Answer: (d).All of the above
10. Data Manipulation Language enables users to
a. Retrieval of information stored in database
b. Insertion of new information into the database
c. Deletion of information from the database
d. All of the above
Answer: (d).All of the above
11. Which of the following is Database Language?
a. Data Definition Language
b. Data Manipulation Language
c. Query Language
d. All of the above
Answer: (d).All of the above
12. Which of the following in not a function of DBA?
a. Network Maintenance
b. Routine Maintenance
c. Schema Definition
d. Authorization for data access
Answer: (a).Network Maintenance
13. Which of the following represents a relationship among a set of values.
a. A Row
b. A Table
c. A Field
d. A Column
Answer: (a).A Row
14. Column header is refer as
a. Table
b. Relation
c. Attributes
d. Domain
Answer: (c).Attributes
15. Which of the following is not Modification of the Database?
a. Deletion
b. Insertion
c. Sorting
d. Updating
Answer: (c).Sorting
16. Which of the following in true regarding Null Value?
a. Null = 0
b. Null < 0
c. Null > 0
d. Null <> 0
Answer: (d).Null <> 0
17. ODBC stands for ______
a. Offline database connection
b. Oriented database connection
c. Open database connection
d. None of the above
Answer: (c).Open database connection
18. _____________ refers to the correctness and completeness of the data in a database?
a. Data security
b. Data integrity
c. Data constraint
d. Data independence
19. Data integrity constraints are used to:
a. Control who is allowed access to the data
b. Ensure that duplicate records are not entered into the table
c. Improve the quality of data entered for a specific property (i.e., table column)
d. Prevent users from changing the values stored in the table
Answer: (c).Improve the quality of data entered for a specific property (i.e., table column)
20. The DBMS acts as an interface between what two components of an enterprise-class database system?
a. Database application and the database
b. Data and the database
c. The user and the database application
Answer: (a).Database application and the database
1. Which of the following is not a level of data abstraction?
a. Physical Level
b. Critical Level
c. Logical Level
d. View Level
Answer: (b).Critical Level
2. Which of the following is not an Schema?
a. Database Schema
b. Physical Schema
c. Critical Schema
d. Logical Schema
Answer: (c).Critical Schema
3. Which of the following is a Data Model?
a. Entity-Relationship model
b. Relational data model
c. Object-Based data model
d. All of the above
Answer: (d).All of the above
4. Logical design of database is called
a. Database Instance
b. Database Snapshot
c. Database Schema
d. All of the above
Answer: (c).Database Schema
5. Snapshot of the dta in the database at a given instant of time is called
a. Database Schema
b. Database Instance
c. Database Snapshot
d. All of the above
Answer: (b).Database Instance
6. Which of the following is the structure of the Database?
a. Table
b. Schema
c. Relation
d. None of these
Answer: (b).Schema
7. A logical description of some portion of database that is required by a user to perform task is called as
a. System View
b. User View
c. Logical View
d. Data View
Answer: (b).User View
8. _____________ is a classical approach to database design?
a. Left – Right approach
b. Right – Left approach
c. Top – Down approach
d. Bottom – Up approach
Answer: (c).Top – Down approach
9. Which of the following is the oldest database model?
a. Relational
b. Hierarchical
c. Physical
d. Network
Answer: (d).Network
10. 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 (GEC)
Answer: (b).Maximum cardinality
11. Which of the following data constraints would be used to specify that the value of cells in a column must be one of a specific set of possible values?
a. A domain constraint
b. A range constraint
c. An intrarelation constraint
d. An interrelation constraint
Answer: (a).A domain constraint
12. In a 1:N relationship, the foreign key is placed in:
a. either table without specifying parent and child tables.
b. the parent table.
c. the child table.
d. either the parent table or the child table.
Answer: (c).the child table.
13. Which of the following column properties specifies whether or not cells in a column must contain a data value?
a. Null status
b. Data type
c. Default value
d. Data constraints
Answer: (a).Null status
14. A primary key should be defined as:
a. NULL
b. NOT NULL
c. Either of the above can be used
d. None of the above are correct
Answer: (b).NOT NULL
15. Which of the following column properties would be used to specify that cells in a column must contain a monetary value?
a. Null status
b. Data type
c. Default value
d. Data constraints
Answer: (b).Data type
16. If a denormalization situation exists with a one-to-one binary relationship, which of the following is true?
a. All fields are stored in one relation.
b. All fields are stored in two relations.
c. All fields are stored in three relations.
d. All fields are stored in four relations.
Answer: (a).All fields are stored in one relation.
17. Selecting a data type involves which of the following?
a. Maximize storage space
b. Represent most values
c. Improve data integrity
d. All of the above
Answer: (c).Improve data integrity
18. What is the best data type definition for Oracle when a field is alphanumeric and has a length that can vary?
a. VARCHAR2
b. CHAR
c. LONG
d. NUMBER
Answer: (a).VARCHAR2
19. A multidimensional database model is used most often in which of the following models?
a. Data warehouse
b. Relational
c. Hierarchical
d. Network
Answer: (a).Data warehouse
20. Which of the following is not a factor to consider when switching from small to large block size?
a. The length of all of the fields in a table row.
b. The number of columns
c. Block contention
d. Random row access speed
Answer: (b).The number of columns
1. A Relation is a
a. Subset of a Cartesian product of a list of attributes
b. Subset of a Cartesian product of a list of domains
c. Subset of a Cartesian product of a list of tuple
d. Subset of a Cartesian product of a list of relations
Answer: (b).Subset of a Cartesian product of a list of domains
2. In mathematical term Table is referred as
a. Relation
b. Attribute
c. Tuple
d. Domain
Answer: (a).Relation
3. In mathematical term Row is referred as
a. Relation
b. Attribute
c. Tuple
d. Domain
Answer: (c).Tuple
4. _______ allow us to identify uniquely a tuple in the relation.
a. Superkey
b. Domain
c. Attribute
d. Schema
Answer: (a).Superkey
5. Minimal Superkeys are called
a. Schema keys
b. Candidate keys
c. Domain keys
d. Attribute keys
Answer: (b).Candidate keys
1. Which of the following is correct regarding Aggregate functions?
a. it takes a list of values and return a single values as result
b. it takes a list of values and return a list of values as result
c. it takes a single value and returns a list of values as result
d. it takes a single value and returns a single value as result
Answer: (a).it takes a list of values and return a single values as result
2. Which of the following option is use to retrieval of data?
a. Stack
b. Data Structure
c. Linked list
d. Query
Answer: (d).Query
3. Establishing limits on allowable property values, and specifying a set of acceptable, predefined options that can be assigned to a property are examples
of:
a. Attributes
b. Data integrity constraints
c. Method constraints
d. Referential integrity constraints
Answer: (b).Data integrity constraints
4. ______ is a special type of integrity constraint that relates two relations & maintains consistency across the relations.
a. Entity Integrity Constraints
b. Referential Integrity Constraint
c. Domain Integrity Constraints
d. Domain Constraints
Answer: (b).Referential Integrity Constraint
5. Which of the following is a physical storage media ?
a. Tape Storage
b. Optical Storage
c. Flash memory
d. All of the mentioned
Answer: (d).All of the mentioned
6. Which of the following creates a virtual relation for storing the query ?
a. Function
b. View
c. Procedure
d. None of the mentioned
7. Which of the following is the syntax for views where v is view name ?
a. Create view v as “query name”;
b. Create “query expression” as view;
c. Create view v as “query expression”;
d. Create view “query expression”;
Answer: (c).Create view v as “query expression”;
1. Disadvantages of File systems to store data is:
a. Data redundancy and inconsistency
b. Difficulty in accessing data
c. Data isolation
d. All of the above
Answer: (d).All of the above
2. Which level of RAID refers to disk mirroring with block striping?
a. RAID level 1
b. RAID level 2
c. RAID level 0
d. RAID level 3
Answer: (a).RAID level 1
3. Optical disk technology uses
a. Helical scanning
b. DAT
c. a laser beam
d. RAID
Answer: (d).RAID
1. State true or false: SQL specifies a way of mentioning functional dependencies
a. True
b. False
c. May be
d. Can't say
Answer: (b).False
2. State true or false: Most current database systems do not support constraints on materialized view
a. True
b. False
c. May be
d. Can't say
Answer: (a).True
3. Multi valued dependencies are also called as __________
a. Equality generating dependencies
b. Tuple generating dependencies
c. Multi-purpose dependencies
d. None of the mentioned
Answer: (b).Tuple generating dependencies
4. Functional dependencies are sometimes referred to as ________
a. Equality generating dependencies
b. Tuple generating dependencies
c. Multi-purpose dependencies
d. None of the mentioned
Answer: (a).Equality generating dependencies
5. The _______ is a set of all functional and multi values dependencies implied by a set of functional dependencies
a. Star
b. Closure
c. Derivation
d. Evolution
Answer: (b).Closure
6. State true or false: If a relational schema is in _______ NF and A is a subset of R and B is also a subset of R then it is that A is a superkey is a trivial multi
values dependency.
a. 1
b. 2
c. 3
d. 4
Answer: (d).4
7. Which of the following normal forms does not exist?
a. BCNF
b. PJNF
c. 5NF
d. None of the mentioned
Answer: (d).None of the mentioned
1. The SQL database language includes statements for:
a. Database definition.
b. Database manipulation.
c. Database control.
d. All of the above.
Answer: (d).All of the above.
2. A command to remove a relation from an SQL database
a. Delete table table name
b. Drop table table name
c. Erase table table name
d. Alter table table name
Answer: (b).Drop table table name
3. Which SQL Query is use to remove a table and all its data from the database?
a. Create Table
b. Alter Table
c. Drop Table
d. None of these
Answer: (c).Drop Table
4. A type of query that is placed within a WHERE or HAVING clause of another query is called
a. Super query
b. Sub query
c. Master query
d. Multi-query
Answer: (b).Sub query
5. Aggregate functions are functions that take a ___________ as input and return a single value.
a. Collection of values
b. Single value
c. Aggregate value
d. Both a & b
6. Select __________ from instructor where dept name= ’Comp. Sci.’;
Which of the following should be used to find the mean of the salary ?
a. Mean(salary)
b. Avg(salary)
c. Sum(salary)
d. Count(salary)
Answer: (b).Avg(salary)
1. 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 above
Answer
(A) Data Model
2. 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
3. In E-R Diagram, weak entity is represented by.......
(A) Rectangle
(B) Square
(C) Double Rectangle
(D) Circle
Answer
(C) Double Rectangle
4. 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
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) Select1. 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 above
Answer
(A) Data Model
2. 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
3. In E-R Diagram, weak entity is represented by.......
(A) Rectangle
(B) Square
(C) Double Rectangle
(D) Circle
Answer
(C) Double Rectangle
4. 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
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
Comments
Post a Comment