Database Concept mcq computer science class 12, CUET mcq computer science, helpful for all competitive exams entrance exams and IT preparation
- Which of the following constraint ignores NULL value?
a. UNIQUE
b. FOREIGN
c. CHECK
d. All of above
Show Answer
b. FOREIGN
- Which is the correct difference between Primary key and Foreign key?
a. A table can have multiple primary key and single foreign key
b. A primary key cannot ignore NULL value but Foreign key can
c. A Primary key can have duplicate data but foreign key does not
d. None of the above
Show Answer
b. A primary key cannot ignore NULL value but Foreign key can
- Which one of the following refers to the copies of the same data (or information) occupying the memory space at multiple places.
a. Data Repository
b. Data Inconsistency
c. Data Mining
d. Data Redundancy
Show Answer
d. Data Redundancy
- Which of the following refers to the number of attributes in a relation?
a. Degree
b. Row
c. Column
d. All of the above
Show Answer
a. Degree
- Consider attributes ID, CITY and NAME. Which one of this can be considered as a primary key?
a. NAME
b. ID
c. CITY
d. CITY, ID
Show Answer
b. ID
- Which of the following is considered as DBMS ?
a. Access
b. Oracle
c. SQL Server
d. All of these
Show Answer
d. All of these
- What will be cardinality and degree for given table ‘coach’?
| Coachid | Coachname | Age | Sport | Dateofapp | Pay | Gender |
| 1 | Karan | 35 | Karate | 27/03/19 | 10000 | M |
| 2 | Ravina | 34 | Karate | 20/01/20 | 12000 | F |
| 3 | Kamal | 34 | Squash | 19/02/20 | 20000 | M |
| 4 | Tarun | 33 | Basketball | 01/01/20 | 15000 | M |
| 5 | Sumeru | 36 | Swimming | 12/01/20 | 7500 | M |
| 6 | Anjani | 36 | Swimming | 24/02/20 | 8000 | F |
| 7 | Shamima | 37 | Squash | 20/02/20 | 22000 | F |
| 8 | Soumya | 30 | Karate | 22/02/20 | 11000 | F |
a. cardinality = 7, degree = 8
b. cardinality = 9, degree = 8
c. cardinality = 7, degree = 56
d. cardinality = 8, degree = 7
Show Answer
d. cardinality = 8, degree = 7
- if degree of relation is 4 that means relation have
a. 4 tuples
b. 4 attributes
c. 4 state
d. 4 relations
Show Answer
b. 4 attributes
- Relational model was developed by
a. E. F Codd
b. Richard Stallman
c. Guido Van Rossum
d. John Von Neumann
Show Answer
a. E. F Codd
- For the given table ‘student’ having fields
admno, rollno, name, class, dob
identify the most suitable field for Primary key
a. Admno
b. Rno
c. Name
d. Class
Show Answer
a. Admno
- A database management system is a _________ type of software
a. System software
b. Application software
c. General software
d. Both (a) and (c)
Show Answer
b. Application software
- Which one of the following refers to the copies of the same data (or information) occupying the memory space at multiple places.
a. Data Repository
b. Data Inconsistency
c. Data Mining
d. Data Redundancy
Show Answer
d. Data Redundancy
- The term ‘Data’ refers to
a. The electronic presentation of the information
b. Basic information
c. Raw facts and figures
d. Both (a) and (c)
Show Answer
c. Raw facts and figures
- Which of the following refers to the number of tuples on a relation?
a. Entity
b. Column
c. Cardinality
d. None of the above
Show Answer
c. Cardinality
- In a relation, which of the following refers to the term ‘attribute’?
a. Entity
b. Row
c. Column
d. Both (b) and (c)
Show Answer
c. Column
- __________ is used to represent the relationship between tables
a. Primary key
b. Foreign key
c. Unique key
d. Candidate key
Show Answer
b. Foreign key
- Order(order_id, ccode, total)
here the order_id, ccode and total are _________ and Order is __________
a. Relation attribute
b. Attribute, relation
c. Degree, relation
d. Relation tuple
Show Answer
b. Attribute, relation
- before DBMS information was stored using ________
a. Data System
b. Memory System
c. File System
d. Drive
Show Answer
c. File System
- Storing records using DBMS helps in
a. Eliminates Data Redundancy
b. Maintain data consistency
c. Controlled data sharing
d. All of the above
Show Answer
d. All of the above
- Collection of logically related records are called
a. Information
b. Relation
c. Database
d. Tuple
Show Answer
b. Relation
- I
ensure every tuple is unique in relation
can be applied to only one attribute in a relation
can not accept NULL values
who am I?
a. Primary key
b. Unique key
c. Foreign key
d. Candidate key
Show Answer
a. Primary key
- Which of the following is a real life application of DBMS?
a. Inventory Management
b. Banking
c. Online Shopping
d. All of the above
Show Answer
d. All of the above
- Database schema refers to
a. Table name and their fields
b. Relationship among tables
c. Data stored in tables
d. (a) and (b)
Show Answer
d. (a) and (b)
- When we define database schema(structure), database state is
a. 0
b. 1
c. Null
d. Equal to degree
Show Answer
a. 0
- In RDBMS, R represents
a. Record
b. Relation
c. Relational
d. Referential
Show Answer
c. Relational
- In a relation tuple represents a
a. Single cell
b. Single row
c. Single column
d. None of the above
Show Answer
b. Single row
- Which following property is not observed with respect to RDBMS?
a. Sequence of attributes in a relation is immaterial
b. Tuples in a relation can be duplicated
c. No attribute can have many data value in one tuple
d. NULL is used to represent values that are unknown or non applicable to certain attributes
Show Answer
b. Tuples in a relation can be duplicated
- Restriction on the type of data that can be inserted into the table is
a. Database Schema
b. Database Instance
c. Database Constraint
d. Database Key
Show Answer
c. Database Constraint
- A tuple is a unique entity whereas attribute values can be duplicated in the table
a. True
b. False
c. Depends upon type of record
d. Depends upon the database key
Show Answer
a. True
- Which of the following is RDBMS?
a. MySQL
b. SQL Server
c. MongoDB
d. All of the above
Show Answer
d. All of the above
- Which of the following represent a valid file system to store records
a. Access
b. MySQL
c. CSV files
d. All of above
Show Answer
c. CSV files
- According to case of Q 33, Roll No 4 may not be interested in sport; can a NULL value be assigned to that student’s preference attribute?
a. Yes
b. No
c. Not Sure
d. Depends upon you
Show Answer
a. Yes
- A school has a rule that each student must participate in a sport activity. So each one should give only one preference for sport activity. So each one should give only one preference for sport activity. Suppose there are five students in a class, each having a unique rollno. The class representative has prepared a list of sports preferences as shown below:
| Rollno | Preference |
| 1 | Cricket |
| 2 | Football |
| 3 | Hockey |
| 4 | NULL |
| 5 | Volley ball |
| Null | Kabaddi |
Kabaddi was not chosen by any student. Is it possible to have this tuple in the Sport preference relation?
a. Yes
b. No
c. Not Sure
d. Depends upon you
Show Answer
b. No
- An organization wants to create a database CUSTOMER-SALE to maintain following details about its items and their sale.
CUSTOMER(Ccode, Cname, Cadd)
SALE( SaleID, CCode, Total)
Name the attributes of Customer which can be candidate key
a. Ccode, Cname
b. Ccode, Cadd
c. Cname, Cadd
d. Ccode
Show Answer
b. Ccode, Cadd
- For the case given in Q34, The organization wants to receive details of SALE of a particular Customer. Name the tables and the key which are required to retrieve this detail.
a. Customer, ccode
b. Sale, ccode
c. Customer and sale, ccode
d. Customer and sale, saleid
Show Answer
c. Customer and sale, ccode
- For the given tables of Q37, find the alternate key in table STUDENT.
a. Rollno
b. Reg_id
c. Class
d. Name
Show Answer
a. Rollno
- For given following tables
| STUDENT | PROJECT ASSIGNEND | ||||
| Rollno | Name | Class | Reg_id | Reg_id | Proj_no |
| 1r04 | Sanjay | 12 | R01 | R01 | 101 |
| 2 | Ram kumar | 12 | R02 | R03 | 102 |
| 3 | Harish | 12 | R03 | R04 | 103 |
| 4 | Jaikaran | 12 | R04 |
Find Foreign Key in PROJECT ASSIGNED table
a. Reg_id
b. Proj_no
c. Both reg_id and Proj_no
d. No Foreign Key defined
Show Answer
a. Reg_id
- _______ is a request to a database for obtaining information in a desired way.
a. Table
b. Query
c. Report
d. Hosting
Show Answer
b. Query
- In which of the following case NULL value cannot be assigned to the column ROLLNO.
a. When the ROLLNO is zero
b. When the ROLLNO is not known
c. When the ROLLNO is not available
d. When the ROLLNO is not applicable
Show Answer
a. When the ROLLNO is zero
- ___________ is used to get the common tuples from two tables.
a. Minus
b. Union
c. Catesian Product
d. Intersection
Show Answer
d. Intersection
Q 34 in DBMS MCQ: How Cadd can be a candidate key as two persons from same house can be customer
Q29 in DBMS MCQ: the statement is true but if the attribute is primary key then we have to consider option4 as well
Q34. The purpose of candidate key is to determine or find the field or set of fields which can ensure entity integrity of DBMS. among those one which can really not have duplicate value is assigned as Primary Key. Candidate keys is about best possible options we can have for primary key. Hence in this Question we have best possible choices are CCode and CAdd.
Q29. You are right, but question is saying Tuple is a unique entity (Tuples must be unique whether database keys are applied or not. )
and
attributes values can be duplicated. (It doesn’t matter database keys are applied are not)
DBMS Integrity Rules says Tuples must be unique not the attribute.
Thanks for putting thoughts.
keep Learning..Best!!