12th Standard Computer Science English Medium Database Concepts Reduced Syllabus Important Questions 2021 | QB365

12th Standard Syllabus & Materials

12th Standard

TN 12th Computer Applications மின்னணு தரவு பரிமாற்றம் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications மின் - வணிக பாதுகாப்பு அமைப்புகள் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications மின்னணு செலுத்தல் முறைகள் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications மின் - வணிகம் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications திறந்த மூல கருத்துருக்கள் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A

12th Standard Computer Science English Medium Database Concepts Reduced Syllabus Important Questions 2021

Published on: 03/02/2021

Download Tamil Nadu 12th Standard Computer Science question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.

Questions + Answers key

Take MCQ Computer Science Test

QB365 Student Learing Managemnet System

Std: 12th Standard - Computer Science

chapter: - Model Question paper

Visit QB365-SLMS - https://www.qb365.in/slms/ Complete Questions and Answers

Questions:

Generic 2

10 x 2 = 20

Write a note on
(i) SELECT Operation
(ii) PROJECT Operation

What is E F Codd rules?

List the types of RDBMS software.

List the characteristics of DBMS.

Differentiate data and information.

What is database?

What is the difference between Hierarchical and Network data model?

What is data consistency?

List some examples of RDBMS.

10.

Mention few examples of a database.

Generic 5

6 x 5 = 30

11.

Explain the components of DBMS.

12.

Explain the characteristics of DBMS.

13.

Explain the different operators in Relational algebra with suitable examples.

14.

Differentiate DBMS and RDBMS.

15.

Explain the different types of relationship mapping.

16.

Explain the different types of data model.

Multiple Choice Question

20 x 1 = 20

17.

___________ is a computer based record keeping system

(a)

Data model

(b)

Data relationships

(c)

DBMS

(d)

Entity relationship

18.

In ____________ data model, the data stores in the form of classes and inheritance.

(a)

Hierarchical

(b)

Entity relationship

(c)

Object

(d)

Network

19.

Doctor and Patient is an example of ________ database model

(a)

ER-model

(b)

Relation

(c)

Object

(d)

Hierarchical

20.

__________ data model provides a clear modular structure of a data

(a)

object

(b)

Relational

(c)

Hierarchical/ER-model

(d)

All of these

21.

__________ database model is an extended form of hierarchical data model

(a)

object

(b)

Relational

(c)

ER model

(d)

Network

22.

Each column in a table represents a ___________

(a)

Record

(b)

Data

(c)

Field

(d)

Method

23.

Who are the one responsible for identifying the data to be stored in the data base?

(a)

DBA

(b)

Application programmers

(c)

End user

(d)

Database designers

24.

Who manages the complete database management system?

(a)

End user

(b)

DBA

(c)

DB designer

(d)

software developer

25.

DBA expansion is

(a)

Data Base Analyst

(b)

Data Base Administrators

(c)

Digital Bound Administrations

(d)

Database Analyser

26.

Which database model is simple and easy to design logical view of database?

(a)

Hierarchical

(b)

Object

(c)

Relational

(d)

ER model

27.

Which of fhe following is not a type of data model?

(a)

Hierarchical model

(b)

Entity Relationship model

(c)

Object model

(d)

Redundancey model

28.

How many types of data models are there?

(a)

(b)

(c)

(d)

29.

Which of the following is a simple abstraction of complex real world data gathering environment?

(a)

Data redundancy

(b)

Data consistency

(c)

Data abstraction

(d)

Data model

30.

Which of the following DBMS components controls everything in a database?

(a)

Hardware

(b)

Square

(c)

Methods

(d)

Procedures

31.

Which of the following is not a DBMS component?

(a)

Hardware/Square

(b)

Data

(c)

Procedures

(d)

Data model

32.

Which of the following provides protection and security to the databases?

(a)

My SQL

(b)

DBMS

(c)

Oracel

(d)

CSV

33.

Which of the following provided an interface to perform various operations to create a database, storing and updating data?

(a)

SQL

(b)

DBA

(c)

DBMS

(d)

Algebra

34.

Which of the following a data contain?

(a)

Character

(b)

text

(c)

Word

(d)

Number

(e)

All of these

35.

Which of the following is an organized collection of data, which can be stared and a cersed through computer system

(a)

Database

(b)

Worksheet

(c)

DBMS

(d)

Information

36.

Which of the following is an organized collection of data?

(a)

Word Processor

(b)

Spreadsheet

(c)

Programming language

(d)

Database

Generic 3

10 x 3 = 30

37.

Write the symbol used for the following.
(i) SELECT
(ii) PROJECT
(iii) Union
(iv) Intersection
(v) Difference
(vi) PRODUCT

38.

List the types of DBMS users.

39.

Write a short note on the database model, in which relationship are created by dividing the object into entity.

40.

Explain the data model that represent parent child relationship.

41.

Write a short note on Relational data model.

42.

List the types of data model.

43.

Write the importance of using data model.

44.

Write a note on database structure.

45.

Write a note on DBMS or write a note on a software that allows us to create, define and manipulate database.

46.

What does the term database refers?

Visit QB365-SLMS - https://www.qb365.in/slms/

Answers Key:

Generic 2

10 x 2 = 20

(i) SELECT Operation (symbol : σ): The SELECT operation is used for selecting a subset with tuples according to a given condition.
(ii) PROJECT Operation (symbol: II): The projection eliminates all attributes of the input relation but those mentioned in the projection list. The projection method defines a relation that contains a vertical subset of Relation.

Database normalization was first proposed by Dr. Edgar F Codd as an integral part of RDBMS in order to reduce data redundancy and improve data integrity. These rules are known as E F Codd Rules.

SQL server, Oracle, MySQL, MariaDB, SQLite.

DBMS Supports Transactions : It allows us to better handle and manage data integrity in real world applications where multi-threading is extensively used.

(i) Data are raw facts stored in a computer. A data may contain any character, text, word or a number.
(ii) Information is formatted data, which allows to be utilized in a significant way.

(i) Database is a repository collection of related data organized in a way that data can be easily accessed, managed and updated.
(ii) Database can be a soft ware or hardware based, with one sole purpose of storing data.

Hierarichal data Model	Network data model
In Hierarchical model, a child record has only one parent node	In a Network model, a child may have many parent nodes,
It Hierarchical model, data is represented as a simple tree like structure form.	It represents the data in many-to-many lationships.

Data Consistency means that data values are the same at all instances of a database.

(i) SQL server
(ii) Oracle
(iii) MySql
(iv) Maria DB
(v) SQLite.

10.

(i) Foxpro
(ii) dbase

Generic 5

6 x 5 = 30

11.

The Database Management System can be divided into five major components as follows:
(i) Hardware
(ii) Software
(iii) Data
(iv) Procedures / Methods
(v) Database Access Languages

(i) Hardware: The computer, hard disk, I/O channels for data, and any other physical component involved in storage of data
(ii) Software: This main component is a program that controls everything. The DBMS software is capable of understanding the Database Access Languages and interprets into database commands for execution.
(iii) Data: It is that resource for which DBMS is designed. DBMS creation is to store and utilize data.
(iv) Procedures/Methods: They are general instructions to use a database management system such as installation of DBMS, manage databases to take backups, report generation, etc
(v) DataBase Access Languages: They are the languages used to write commands to access, insert, update and delete data stored in any database.
Examples of popular DBMS: Dbase, FoxPro

12.

Characteristics of Database Management System

1. Data stored into Table	Data is never directly stored into the database. Data is stored into tables, created inside the database. DBMS also allows to have relationship between tables which makes the data more meaningful and connected.
2. Reduced Redundancy	In the modern world hard drives are very cheap, but earlier when hard drives were too expensive, unnecessary repetition of data in database was a big problem But DBMS follows Normalisation which divides the data in such a way that repetition is minimum.
3. Date Consistency	On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it by itself.
4. Support Multiple user and Concurrent Access	DBMS allows multiple users to work on it( update, insert, delete data) at the same time and still manages to maintain the data consistency.
5. Query Language	DBMS provides users with a simple query language, using which data can be easily fetched, inserted, deleted and updated in a database.
6. Security	The DBMS also takes care of the security of data, protecting the data from unauthorized access. In a typical DBMS, we can create user accounts with different access permissions, using which we can easily secure our data by restricting user access.
7. DBMS Supports Transactions	It allows us to better handle and manage data integrity in real world applications where multi-threading is extensively used.

13.

Relational Algebra is divided into various groups
Unary Relational Operations.
(i) SELECT (symbol: σ)
(ii) PROJECT ( symbol: π)
Relational Algebra Operations from Set Theory:
(i) UNION (U)
(ii) INTERSECTION (∩)
(iii) DIFFERENCE (-)
(iv) CARTESIAN PRODUCT (X)
SELECT (symbol: σ)
(i) General from σ (R) with a relation R and a condition C on the attributes of R
(ii) The SELECT operation is used for selecting a subset with tuples according to a given condition.
(iii) Select filters out all tuples that do not satisfy C
STUDENT:

Studio	Name	Course	Year
CS1	Kannan	Big Data	II
CS2	Gowri Shankar	R language	I
CS3	Lenin	Big Data	I
CS4	Padmaja	Python Programming	I

σ course = "Big Data" (STUDENT)

Studio	Name	Course	Year
CS1	Kannan	Big Data	II
2	Lenin	Big Data	I

PROJECT (symbol: II)
(i) The projection eliminates all attributes of the input relation but those mentioned in the projection list.
(ii) The projection method defines a relation that contains a vertical subset of Relation.
Example: 1
II_course (STUDENT)
Result:

Course

Big Data

R language

Python Programming

Example 2
II_{student,course} (STUDENT)
Result:

Stud no	Course
CS1	Big Data
CS2	R language
CS3	Big Data
CS4	Python Programming

UNION (Symbol: U)
(i) It includes all tuples that are in tables A or in B. It also eliminates duplicates. Set A Union Set B would be expressed as A U B
Example 3:

Table A
Studio	Name
CS1	Kannan
CS2	Lenin
CS3	Padmaja

Table A
Studio	Name
CS1	Kannan
CS2	Gowrishakaran
CS3	Lenin

Result:

Table A
Studio	Name
CS1	Kannan
CS2	Gowri Shakaran
CS3	Lenin
CS4	Padmaja

SET DIFFERENCE (Symbol: -)
(i) The result of A - B, is a relation which includes all tuples that are in A but not in B.
(ii) The attribute name of A has to match with the attribute name in B.
Example: 4
using Table B Example 3
Result:

Table A - B
CS4	Padmaja

INTERSECTION (symbol: ∩) A ∩ B:
(i) Defines a relation consisting of a set of all tuple that are in both in A and B. However, A and.B must be union-compatible.
Example: 5
Using Table in Example 3
Result:

Table A - B
CS1	Kannan
CS3	Lenin

PRODUCT OR CARTESIAN PRODUCT (Symbol: X)
(i) Cross product is a way of combining two relations. The resulting relation contains, both relations being combined.
(ii) A x B means A times B, where the relation A and B have different attributes.
(iii) This type of operation is helpful to merge columns from two relations.

14.

Basis of Comparison	DBMS	RDBMS
Expansion	Database Management System	Relational Database Management System
Data storage	Navigational model ie data by linked records	Relational model (in tables). ie data in tables as row and column
Data redundancy	Exhibit	Not Present
Normalization	Not performed	RDBMS uses normalization to reduce redundancy
Data access	Consumes more time	Faster, compared to DBMS.
Keys and indexes	Does not use.	used to establish relationship. Keys are used in RDBMS.
Transaction management	Inefficient, Error prone and insecure	Efficient and secure
Distributed Databases	Not supported	Supported by RDBMS.
Example	Dbase, FoxPro.	SQL server, Oracle, mysql, MariaDB, SQLite.

15.

Types of relationships:
(i) One-to-One Relationship
(ii) One-to-Many Relationship
(iii) Many-to-One Relationship
(iv) Many-to-Many Relationship
(i) One-to-One Relationship:
In One-to-One Relationship, one entity is related with : only one other entity. One row in a table is linked with only one row in another table and vice versa.
For example: A student can have only one exam number

(ii) One-to-Many Relationship.
In One-to- Many relationship, one entity is related to many other entities. One row in a table A is linked to many rows in a table B, but one row in a table B is linked to only one row in table A.
For example: One Department has many staff members.

(iii) Many-to-One Relationship:
In Manyto- One Relationship, many entities can be related with only one in the other entity.
For example:
A number of staff members working in one Department.
Multiple rows in staff members table is related with only one row in Department table.

(iv) Many-to-Many Relationship:
A manyto- many relationship occurs when multiple records in a table are associated with multiple records in another table.
(i) Example 1:
Customers and Product
Customers can purchase various products and Products can be purchased by many customers
(ii) Example 2:
Students and Courses
A student can register for many Courses and a Course may include many students
(iii) Example 3:
Books and Student.
Many Books in a Library are issued to many students.

16.

Types of a Data Model:
1. Hierarchical Model
2. Relational Model
3. Network Database Model
4. Entity Relationship Model
5. Object Model.
1. Hierarchical Model:
(i) Hierarchical model was developed by IBM as Information Management System. In Hierarchical model, data is represented as a simple tree like structure form.
(ii) This model represents a one-to-many relationship i.e., parent-child relationship. One child can have only one parent but one parent can have many children.
(iii) This model is mainly used in IBM Main Frame computers.

2. Rational Model:
(i) The Relational Database model was first proposed by E.F. Codd in 1970. Nowadays, it is the most widespread data model used for database applications around the world.
(ii) The basic structure of data in relational model is tables (relations). All the information's related to a particular type is stored in rows of that table.
(iii) Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple (row in a relation (table)).

3. Network Model:
Network database model is an extended form of hierarchical data model. The difference between hierarchical and Network data model is:
(i) In hierarchical model, a child record has only one parent node,
(ii) In a Network model, a child may have many parent nodes. It represents the data in many-to-many relationships.
(iii) This model is easier and faster to access the data.

(iv) School represents the parent node
(v) Library, Office and Staff room is a child to school (parent node)
(vi) Student is a child to library, office and staff room (one to many relationship)
4. Entity Relationship Model:
(i) In this database model, relationship are created by dividing the object into entity and its characteristics into attributes.
(ii) It was developed by Chen in 1976. This model is useful in developing a conceptual design for the database. It is very simple and easy to design logical view of data. The developer can easily understand the system by looking at ER model constructed.
(iii) Rectangle represents the entities. E.g. Doctor and Patient.
(iv) Ellipse represents the attributes E.g. D-id, D-name, P-id, P-name. Attributes describes the characteristics and each entity becomes a major part of the data stored in the database. Diamond represents the relationship in ER diagrams e.g; Doctor diagnosis the Patient.

5. Object Model:
(i) Object model stores the data in the form of objects, attributes and methods, classes and Inheritance.
(ii) This model handles more complex applications, such as Geographic information System (GIS), scientific experiments, engineering design and manufacturing.
(iii) It is used in file Management System. It represents real world objects, attributes and behaviors. It provides a clear modular structure. It is easy to maintain and modify the existing code.

(iv) An example of the Object model is Shape, Circle, Rectangle and Triangle are all objects in this model.
(i) Circle has the attribute radius.
(ii) Rectangle has the attributes length and breadth.
(iii) Triangle has the attributes base and height.
(iv) The objects Circle, Rectangle and Triangle inherit from the object Shape.

Multiple Choice Question

20 x 1 = 20

17.

18.

19.

(a)
ER-model

20.

(a)
object

21.

(d)
Network

22.

23.

(d)
Database designers

24.

(b)
DBA

25.

(b)
Data Base Administrators

26.

(d)
ER model

27.

(d)
Redundancey model

28.

29.

(d)
Data model

30.

(b)
Square

31.

(d)
Data model

32.

(b)
DBMS

33.

34.

(e)
All of these

35.

(a)
Database

36.

(d)
Database

Generic 3

10 x 3 = 30

37.

(i) σ
(ii) π
(iii) U
(iv) ∩
(v) -
(vi) X

38.

(i) Database Administrators(DBA)
(ii) Application or software developers
(iii) End User
(iv) Database designers

39.

Entity Relationship Model (ER model):
(i) In this database mo-ad., relationship are created by dividing the object into entity and its characteristics into attributes.
(ii) It was developed by Chen in 1976. This model is useful in developing a conceptual design for the database.
(iii) It is very simple and easy to design logical view of data. The developer can easily understand the system by looking at ER model constructed.

40.

(i) Hierarchical model was developed by IBM as Information Management System.
(ii) In Hierarchical model, data is represented as a simple tree like structure form. This model represents a one-to-many relationship ie parent-child relationship.
(iii) One child can have only one parent but one parent can have many children. This model is mainly used in IBM Main Frame computers.

41.

(i) The Relational Database model was first proposed by E.P. Codd in 1970. It is the most widespread data model used for database applications around the world.
(ii) The basic structure of data in relational model is tables (relations). All the information's related to a particular type is stored in rows of that table.
(iii) Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple (row in a relation (tabler).

42.

The different types of a Data Model
(i) Hierarchical Model
(ii) Relational Model
(iii) Network Database Model
(iv) Entity Relationship Model
(v) Object Model

43.

(i) A data model describes how the data can be represented and accessed from a software after complete implementation
(ii) It is a simple abstraction of complex real world data gathering environment.
(iii) The main purpose of data model is to give an idea as how the final system or software will look like after development is completed.

44.

(i) Table is the entire collection of related data in one table, referred to as a File or Table where the data is organized as row and column.
(ii) Each row in a table represents a record, which is a set of data for each database entry.
(iii) Each table column represents a Field, which groups each piece or item of data among the records into specific categories or types of data. Eg. StuNo., StuName, StuAge, StuClass, StuSec.,
A Table is known as a RELATIQN
A Row is known as a TUPLE
A column is known as an ATTRIBUTE

45.

(i) A DBMS is a soft ware that allows us to create, define and manipulate database, allowing users to store, process and analyze data easily.
(ii) DBMS provides us with an interface or a tool, to perform various operations to create a database, storing of data and for updating data, etc.
(iii) DBMS also provides protection and security to the databases. It also maintains data consistency in case of multiple users.

46.

(i) A database is an organized collection of data, generally stored and accessed electronically from a computer system.
(ii) The term "database" is also used to refer to any of the DBMS, the database system or an application associated with the database
(iii) Because of the close relationship between them, the term "database" is often used casually to refer to both a database and the DBMS used to manipulate it.