Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 3 Introduction to Database Management System Text Book Back Questions and Answers, Notes.
Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 3 Introduction to Database Management System
12th Computer Applications Guide Introduction to Database Management System Text Book Questions and Answers
Part I
Choose The Correct Answers
Question 1.
Which language is used to request information from a Database?
a) Relational
b) Structural
c) Query
d) Compiler
Answer:
c) Query
Question 2.
The …………….. diagram gives a logical structure of the database graphically?
a) Entity-Relationship
b) Entity
c) Architectural Representation
d) Database
Answer:
a) Entity-Relationship
Question 3.
An entity set that does not have enough attributes to form a primary key is known as
a) Strong entity set
b) Weak entity set
c) Identity set
d) Owner set
Answer:
b) Weak entity set
Question 4.
_____ Command is used to delete a database.
a) Delete database database_name
b) Delete database_name
c) drop database database_name
d) drop database_name
Answer:
c) drop database database_name
Question 5.
Which type of below DBMS is MySQL?
a) Object-Oriented
b) Hierarchical
c) Relational
d) Network
Answer:
c) Relational
Question 6.
MySQL is freely available and is open source.
a) True
b) False
Answer:
a) True
Question 7.
……………….. represents a “tuple” in a relational database?
a) Table
b) Row
c) Column
d) Object
Answer:
b) Row
Question 8.
Communication is established with MySQL using
a) SQL
b) Network calls
c) java
d) API’s
Answer:
a) SQL
Question 9.
Which is the MySQL instance responsible for data processing?
a) MySQL Client
b) MySQL Server
c) SQL
d) Server Daemon Program
Answer:
c) SQL
Question 10.
The structure representing the organizational view of the entire database is known as _____ In MySQL database.
a) Schema
b) View
c) Instance
d) Table
Answer:
a) Schema
Part II
Short Answers
Question 1.
Define Data Model and list the types of data model used.
Answer:
Data models define how the logical structure of a database is modeled.
Data models define how data is connected to each other and how they are processed and stored inside the system. The various data models are;
- Hierarchical Database Model,
- Network Model,
- Relational Model and
- Object-oriented Database Model.
Question 2.
List few disadvantages of the file processing system.
Answer:
Data Duplication – Same data is used by multi¬ple resources for processing, thus created multiple copies of the same data wasting the spaces.
High Maintenance – Access control and verify- ing data consistency needs high maintenance cost.
Security – Less security provided to the data.
Question 3.
Define Single and multi-valued attributes.
Answer:
A single-valued attribute contains only one value for the attribute and they don’t have multiple numbers of values. For Example Age.
A multi-valued attribute has more than one value for that particular attribute. For Example Degree.
Question 4.
List any two DDL and DHL commands with its Syntax.
Answer:
DDL Commands:
| Commands | Syntax |
| CREATE | CREATE database databasename; |
| DROP | DROP database databasename; |
DML Commands:
| Commands | Syntax |
| INSERT | INSERT INTO table name VALUES (value1, value2, values); |
| DELETE | DELETE from table name WHERE columnname=”value”; |
Question 5.
What are the ACID properties?
Answer:
ACID Properties – The acronym stands for Atomicity, Consistency, Isolation and Durability. Atomicity follows the thumb rule “All or Nothing” while updating the data in the database for the user performing the update operation. Consistency ensures that the changes in data value to be constant at any given instance. Isolation property is needed during concurrent action. Durability is defined as the system’s ability to recover all committed actions during the failure of storage or the system.
Question 6.
Which command is used to make permanent changes done by a transaction?
Answer:
- These SQL commands manage the transactions in SQL databases.
- It also helps to save the change into the database permanently.
- COMMIT, ROLLBACK, SET TRANSACTION, and SAVEPOINT commands belong to this category.
Question 7.
What is a view in SQL?
Answer:
Views – A set of stored queries.
Question 8.
Write the difference between SQL and MySQL.
Answer:
| SQL | MySQL |
| SQL is a query language. | MySQL is database software. |
| To query and operate a database system. | Allows data handling, storing, modifying, deleting in a tabular format. |
Question 9.
What is a Relationship and List its types?
Answer:
One-to-One relationship
One-to-Many relationship
Many-to-Many relationship
Question 10.
State a few advantages of Relational databases.
Answer:
- High Availability
- High Performance
- Robust transfer actions and support
- Ease of management
- Less cost
Part III
Explain In Brief Answer
Question 1.
Explain on Evolution of DBMS.
Answer:
- The concept of storing the data started 40 years in various formats.
- In earlier days they have used punched card technology to store the data.
- Then files were used. The file systems were known as the predecessor of the database system.
- Various access methods in the file system were indexed, random, and sequential access.
- The file systems have limitations like duplication, less security. To overcome this, DBMS was introduced.
Question 2.
What is a relationship in databases? List its types.
Answer:
There exists a relationship between two tables when the foreign key of one table references the primary key of other tables.
The Entity-Relationship(ER) diagram is based on the three types listed below.
- One-to-One relationship
- One-to-Many relationship
- Many-to-Many relationship
Question 3.
Discuss on Cardinality in DBMS.
Answer:
- It is defined as the number of different values in any given table column
- It Is defined as the number of items that must be II included in a relationship.ie) number of entities | in one set mapped with the number of entities of I another set via the relationship,
- Three classifications in Cardinality are one-to-one, jl one-to-many and Many-to-Many.
Question 4.
List any 5 privileges available in MySQL for the User.
Answer:
| Privileges |
Action Performed (If Granted) |
| Select_priv | User can select rows from database tables. |
| Insert_priv | User can insert rows into database tables. |
| Update_priv | User can update rows of database tables. |
| Deiete^priv | User can delete rows of database tables. |
| Create_priv | User can create new tables in database |
Question 5.
Write few commands used by DBA to control the entire database.
Answer:
USE Database
This command is used to select the database in MySQL for working.
Syntax: mysql>use test;
SHOW Databases
Lists all the databases available in the database server,
Syntax: mysql>show databases;
SHOW Tables
Lists all the tables available in the current database we are working in.
Syntax: mysql>show tables;
Part IV
Explain In Detail
Question 1.
Discuss on various database model available in DBMS.
Answer:
The major database models are listed below:
- Hierarchical Database Model
- Network model
- Relational model
- Object-oriented database mode!
Hierarchical Database Model
- In this model each record has information in par-ent/child relationship like a tree structure.
- The collection of records was called as record types, which are equivalent to tables in relational model.
- The individual records are equal to rows.
- The famous Hierarchical database model was IMS (Information Management System), IBM’s first DBMS,
Advantages:
- Less redundant data
- Efficient search
- Data integrity
- Security
Limitations:
- Complex to implement and difficult in handling
- Many to many relationships
Network model
- The network model is similar to the Hierarchical model except that in this model each member can have
more than one owner. - The many to many relationships are handled in a better way.
- This model identified the three database components
- Network schema – Defines all about the structure of the database
- Sub schema – Controls on views of the database for the user.
- Language for data management – Basic procedural for accessing the database.
Relational model:
Oracle and DB2 are few commercial relational models in use.
The relational model is defined with two terminologies Instance and Schema.
- Instance – A table consisting of rows and columns
- Schema – Specifies the structure including the name and type of each column.
A relation (table) consists of unique attributes (columns) and tuples (rows).
Object-oriented database model
- This model incorporates the combination of Object-Oriented Programming(OOP’s) concepts and database technologies.
- Practically, this model serves as the base of the Relational model.
- The object-oriented model uses small, reusable software known as Objects.
- These are stored in an object-oriented database.
- This model efficiently manages a large number of different data types.
- Moreover, complex behaviors are handled efficiently using OOP’s concepts.
Question 2.
List the basic concepts of ER Model with suitable examples.
Answer:
The basic concepts of ER model consist of
- Entity or Entity type
- Attributes
- Relationship
These are the general concepts which help to create an ER diagram and produce an ER model.
Entity or Entity type:
- An Entity can be anything a real-world object or animation which is easily identifiable by anyone even by a common man.
- Example: In a company’s database Employees, HR, Manager are considered entities.
- An entity is represented by a rectangular box.
Types of Entity:
- Strong Entity
- Weak Entity
- Entity Instance
Strong Entity
- A Strong entity is the one which doesn’t depend on any other entity on the schema or database
- A strong entity will have a primary key with it.
- It is represented by one rectangle
Weak Entity
- A weak entity is dependent on other entities and it doesn’t have any primary key like the Strong entity.
- It is represented by a double rectangle.
Entity Instance
- Instances are the values for the entity if we consider animals as the entity their instances will be dog, cat, cow… Etc.
- So an Entity Instance denotes the category values for the given entity.
Attributes:
- An attribute is the information about that entity and it will describe, quantify, classify, and specify an entity.
- An attribute will always have a single value, that value can be a number or character or string.
Types of attributes:
- Key Attribute
- Simple Attributes
- Composite Attributes
- Single Valued Attribute
- Multi-Valued Attribute
Relationship:
There exists a relationship between two tables when the foreign key of one table references primary key of other table.
The Entity-Relationship(ER) diagram is based on the three types listed below.
- One-to-One relationship
- One-to-Many relationship
- Many-to-Many relationship
Question 3.
Discuss in detail various types of attributes in DBMS.
Answer:
Types of attributes:
1. Key Attribute:
Generally, a key attribute describes a unique characteristic of an entity.
2. Simple Attribute:
- The simple attributes cannot be separated it will be having a single value for their entity.
- For Example: Let us consider the name as the attribute for the entity employee and here the value for that attribute is a single value.
3. Composite Attributes:
- The composite attributes can be sub divided into simple attributes without change in the meaning of that attribute.
- For Example: In the above diagram the employee is the entity with the composite attri¬bute Name which are sub-divided into two simple attributes first and last name.
4. Single Valued Attributes;
- A single valued attribute contains only one value for the attribute and they don’t have multiple numbers of values.
- For Example: Age- It is a single value for a person as we cannot give n number of ages for a single person; therefore it is a single valued attribute.
5. Multi-Valued Attributes:
- A multi valued attribute has more than one value for that particular attribute.
- For Example: Degree – A person can hold n number of degrees so it is a multi-valued attribute.
Question 4.
Write a note on open-source software tools available in MySQL Administration.
Answer:
- MySQL is open source software that allows managing relational databases.
- It also provides the flexibility of changing the source code as per the needs.
- It runs on multiple platforms like Windows, Linux and is scalable, reliable and fast.
PHPMYADMIN (Web Admin)
- This administrative tool of MySQL is aweb application written in PHP. They are used predominantly in web hosting.
- The main feature is providing web interface,- importing data from CSV and exporting data to various formats.
- It generates live charts for monitoring MySQL server activities like connections, processes and memory usage. It also helps in making the complex queries easier.
MySQL Workbench (Desktop Application)
- It is a database tool used by developers and DBA’s mainly for visualization.
- This toolhelps in data modeling, development of SQLServer configuration and backup for MySQLin a better way.
- Its basic release version is 5.0and is now in 8.0 supporting all Operating Systems.
- The SQL editor of this tool is veryflexible and comfortable in dealing multiple results set.
HeidiSQL (Desktop Application)
- This open source tools helps in the administra-tion of better database systems.
- It supports GUI (Graphical User Interface) features for monitoring server host, server connection, Databases, Tables, Views, Triggers and Events.
Question 5.
Explain in detail on Sub Queries with suitable examples.
Answer:
- The SQL query is written within amain Query.
- This is called Nested Inner/SubQuery.
- The sub query is executed first and the results of sub query are used as the condition for main query.
The sub query must follow the below rules:
- Subqueries are always written within the parentheses.
- Always place the Subquery on the right side of the comparison operator.
- ORDER BY clause is not used insub query, since Subqueries cannot manipulate the results internally.
Example: (Consider the Employee tablewith the fields EmpID, Name, Age andSalary.)
SELECT * from Employee WHERE EmpID IN (SE-LECT EmpID from Employee WHERE Salary 20000);
First, the inner query is executed. Then outer query will be executed.
12th Computer Applications Guide Introduction to Database Management System Additional Important Questions and Answers
Part A
Choose The Correct Answers:
Question 1.
Expand DBMS?
(a) Database Management System
(b) Data Manipulation Schema
(c) Data Base Management Schema
(d) DataBase Manipulation Schema
Answer:
(a) Database Management System
Question 2.
DBMS provides to ………………… data
a) create
b) retrieve
c) update
d) all of the above
Answer:
d) all of the above
Question 3.
Expand ODBMS.
(a) Object DataBase Management System
(b) Objective Data Base Management System
(c) Object-Oriented DataBase Management System
(d) Objective Data Manipulation System
Answer:
(a) Object DataBase Management System
Question 4.
……………. is defined as the system’s ability to recover all committed transactions during the failure of storage or the system.
a) Durability
b) Consistency
c) Concurrency
d) All of the above
Answer:
a) Durability
Question 5.
Which of the following is a commercial relational models in use.
a) Oracle
b) DB2
c) PostgreSQL
d) Both a and b
Answer:
d) Both a and b
Question 6.
To prevent conflict in database updates, the transactions are isolated from other users and serialized. This is called as ……………………….
(a) Atomicity
(b) Consistency
(c) Isolation
(d) Degree of Consistency
Answer:
(d) Degree of Consistency
Question 7.
A key with more than one attribute to identify rows uniquely in a table is called…………….
a) Candidate Key
b) Super Key
c) Foreign Key
d) Composite Key
Answer:
d) Composite Key
Question 8.
An ……………. can be anything a real-world object or animation
a) Data
b) Entity
c) Instance
d) Relationship
Answer:
b) Entity
Question 9.
Concurrency control and locking are needed
(a) Consistency
(b) data sharing
(c) data hiding
(d) TrAnswer:action
Answer:
(b) data sharing
Question 10.
………… describes a unique characteristic of an entity.
a) Key Attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
a) Key Attribute
Question 11.
………… can be subdivided into simple attributes without change in the meaning of that attribute.
a) Key Attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
c) Composite Attributes
Question 12.
A …………. contains only one value for the attribute and they don’t have multiple numbers of values.
a) Key Attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
d) Single Valued Attribute
Question 13.
IBM’s first DBMS is ……………………..
(a) IMS
(b) IVS
(c) BMS
(d) VMS
Answer:
(a) IMS
Question 14.
A ……………. has more than one value for that particular attribute.
a) Multi-valued attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
a) Multi-valued attribute
Question 15.
The parent-child relationship is established in …………………….. database Models.
(a) Hierarchical
(b) Network
(c) Relational
(d) Object
Answer:
(a) Hierarchical
Fill in the Blanks:
1. ………………is known a predecessor of database system
Answer:
File system
2. MySQL is a database management system founded by…………………
Answer:
Monty Widenius
3. ……………who takes care of configuration, installation, performance, security and data backup.
Answer:
Database Administrators
4. …………….. is a web application written in PHP
Answer:
PHPMYADMIN
5. ………………tool of MySQL is a web application written in PHP.
Answer:
PHPMYADMIN
6. ………………….. is a database tool used by developers and DBA’s mainly for visualization.
Answer:
MySQL Workbench
Question 7.
The ……………….. of this tool is very flexible and comfortable in dealing with multiple results set.
Answer:
SQL editor
Question 8.
…………………….. is a program or process of copying table contents into a file for future reference
Answer:
Backup
Question 9.
SQL query is written within a main Query is called as
Answer:
Sub Query
Question 10.
An attribute is the information about that …………………
Answer:
Entity
Abbrevation
1. DBMS – Database Management System.
2. RDBMS – Relation Database Management System.
3. OSBMS – Objective Database Management System.
4. ACID – Automicity, Consistency, Isolation, And Durability.
5. IMS – Information Management System.
6. IDS – Integrated Data Store.
7. OOP’S – Object Oriented Programming.
8. SQL – Structure Query Language.
9. ER – Entity Relationship.
10. DBA – Database Administration.
11. ANSI – American National Standards Institute.
12. ISO – International Organization For Standardization.
13. DDL – Data Definition Language.
14. DML – Data Manipulation Language.
15. DQL – Data Query Language.
16. TCL – Transaction Control Language.
17. DCL – Data Control Language.
Assertion And Reason
Question 1.
Assertion (A): database management system (DBMS) is system software for creating and managing databases.
Reason (R): The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.”
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
Question 2.
Assertion (A) : In a database, we would be grouping only related data together and storing them under one group name called table.
Reason (R): This helps in identifying which data stored where and under what name.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) ¡s true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
Question 3.
Assertion (A): Oracle and DB2 are few commercial relational models in use.
Reason (R): Relational model is defined with two terminologies Instance and Schema.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) ¡s true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
Question 4.
Assertion (A): A single-valued attribute con¬tains only one value for the attribute and they don’t have multiple numbers of values.
Reason (R): Age – It is a single value for a person as we cannot give n number of ages for a single person, therefore it is a single-valued attribute.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) Is false
d) (A) is false and (R) is true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
Question 5.
Assertion (A): Cardinality is defined as the number of items that must be included in a relationship.ie) number of entities in one set mapped with the number of entities of another set via the relationship.
Reason (R): Three classifications in Cardinality areMany-to-one, one-to-many and Many-to-Many,
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false
Question 6.
Assertion (A): The Database Administrator (DBA) frequently uses few commands to control the entire database.
Reason (R): These commands are known as SQL Server Commands.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false
Question 7.
Assertion (A); Subqueries are always written within the braces.
Reason (R): ORDER BY clause is not used in sub query, since Subqueries cannot manipulate the results internally.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
d) (A) is false and (R) is true
Question 8.
Assertion (A); TCL commands manage the transactions in SQL databases. It also helps to save the change into database permanently.
Reason (R) : CREATE, ALTER, DROP, RENAME and TRUNCATE commands belongs to TCL category.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false
Question 9.
Assertion (A); A Strong entity is the one which doesn’t depend on any other entity on the schema or database and a strong entity will have a primary key with it
Reason (R): It is represented by one rectangle.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is faise
d) (A) is false and (R) is true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
Question 10.
Assertion (A) ; A weak entity is dependent on other entitles and it doesn’t have any primary key like the Strong entity.
Reason (R): It is represented by Diamond,
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false
Find the odd one on the following:
1. (a) Sorting
(b) Retrieving
(c) Filtering
(d) Aligning
Answer:
(d) Aligning
2. (a) Creating
(b) Updating
(c) Managing
(d) Converting
Answer:
(d) Converting
3. (a) Data Duplication
(b) Data Flexibility
(c) Data Maintenance
(d) Security
Answer:
(c) Data Maintenance
4. (a) Access
(b) SQL
(c) Oracle
(d) Notepad
Answer:
(b) SQL
5. (a) Consistency
(b) Durability
(c) Activity
(d) Isolation
Answer:
(c) Activity
6. (a) DBMS
(b) Network Schema
(c) Subschema
(d) Language
Answer:
(a) DBMS
7. (a) id:int
(b) name:int
(c) Nfname:string
(d) email:string
Answer:
(b) name:int
8. (a) Table
(b) attribute
(c) files
(d) Tuples
Answer:
(c) files
9. (a) Class
(b) Object
(c) Data
(d) Abstraction
Answer:
(c) Data
10. (a) Schema
(b) Key
(c) Tuple
(d) Cell
Answer:
(d) Cell
11. (a) Windows
(b) Linux
(c) MACOS
(d) MSSQLServer
Answer:
(d) MSSQLServer
12. (a) Row
(c) Record
(b) attribute
(d) Tuple
Answer:
(b) attribute
13. (a) Vertical Entity
(b) Attribute
(c) Tuple
(d) column
Answer:
(c) Tuple
14. (a) primary Key
(b) Secondary Key
(c) SuperKey
(d) Foreign Key
Answer:
(b) Secondary Key
15. (a) Strong Entity
(c) Super Entity
(b) Weak Entity
(d) Entity Instance
Answer:
(c) Super Entity
16. (a) Schema
(b) Database
(c) primary Key
(d) Foreign Key
Answer:
(d) Foreign Key
17. (a) Degree
(b) Bank Account
(c) Age
(d) Subjects
Answer:
(c) Age
18. (a) One:Unary
(b) Two: Binary
(c) Three:Ternary
(d) Four: penta
Answer:
(d) Four: penta
19. (a) Rectangle
(b) Square
(c) Rhombus
(d) Ellipse
Answer:
(b) Square
20. (a) DB2
(b) Netfix
(c) SQL Lite
(d) Oracle
Answer:
(b) Netfix
21. (a) Configuration
(b) Installation
(c) Performance
(d) Access
Answer:
(d) Access
22. (a) INSERT
(b) EDIT
(c) SELECT
(d) UPDATE
Answer:
(b) EDIT
23. (a) Select_Priv
(b) Delete_Priv
(c) create_Priv
(d) Edit_Priv
Answer:
(d) Edit_Priv
24. (a) MySQL
(b) Workbench
(c) PHPMYADMIN
(d) HeidiSQL
Answer:
(c) PHPMYADMIN
25. (a) ServerHost
(b) Server Connection
(c) Events
(d) processor
Answer:
(d) processor
26. (a) Dashboard
(b) Reports
(c) Table
(d) Statistics
Answer:
(c) Table
27. (a) Table
(b) Insert
(c) Queries
(d) Views
Answer:
(b) Insert
28. (a) TRUNCATE
(b) RENAME
(c) SELECT
(d) ALTER
Answer:
(c) SELECT
29. (a) DDL
(b) DML
(c) HeidiSQL
(d) DQL
Answer:
(c) HeidiSQL
30. (a) ANY
(b) AND
(c) UNIQUE
(d) XOR
Answer:
(d) XOR
MAtch the following:
1. Hierarchical Database – Sybase
2. Network Database – Rhombus
3. Relational Database – Multivalued Attribute
4. Column – Candidate Key
5. Row – Record
6. Primary key – Attribute
7. Super Key – Unique Key Identifier
8. Double Ellipse – Oracle
9. Relationships – IMS
10. Database – IDS
Answer:
1. IMS
2. IDS
3. Oracle
4. Attribute
5. Record
6. Unique Key
7. Candidate Key
8. Multivalued Attribute
9. Rhombus
10. Sybase
Choose the incorrect statements:
Question 1.
a) SQL It (Structured query Language) is a programming language designed mainly for . managing data in RDBMS
b) Schema Retrieves data from two or more tables, by referencing columns in the tables that hold identical values
c) Query In SQL, all commands are named as query. The query statement is executed against the databases.
d) Record is referred in a table, which are composed of fields.
Answer:
b) Schema Retrieves data from two or more tables, by referencing columns in the tables that hold identical values
Question 2.
a) A Record is the information about that entity and it will describe, quantify, qualify, classify, and specify an entity.
b) Cardinality is defined as the number of items that must be included in a relationship
c) A multi-valued attribute has more than one value for that particular attribute.
d) A single-valued attribute contains only one value for the attribute and they don’t have multiple numbers of values.
Answer:
a) A Record is the information about that entity and it will describe, quantify, qualify, classify, and specify an entity.
Question 3.
a) Network schema defines all about the structure of the database.
b) Sub schema controls on views of the database for the user
c) The famous Hierarchical database model was IDS
d) Language is the basic procedural for accessing the database.
Answer:
c) The famous Hierarchical database model was IDS
Question 4.
a) A table consisting of rows and columns
b) Schema – Specifies the structure including name and type of each column.
c) A relation consists of unique attributes and tuples.
d) Query is referred in a table, which are composed of fields.
Answer:
d) Query is referred in a table, which are composed of fields.
Question 5.
a) DCL commands manage the transactions
b) The DML commands deals with the manipulation of data present in the database
c) SELECT is the only SQL command used to fetch or retrieve the data from database tables that come under DQL.
d) The DDL commands are used to define database schema (Structure)
Answer:
a) DCL commands manage the transactions
Syntax & Example (Basic Sql Commands)
1) CREATE DATABASE:
Syntax: CREATE database databasename;
Example: mysql> create database studentDB;
2) DROP DATABASE:
Syntax: DROP database databasename;
Example: mysql> drop database studentDB;
3) SELECT DATABASE
Syntax: USE databasename;
Example: mysqi> USE studentDB;
4) INSERT RECORD
Syntax 1: INSERT INTO tablename (columnl, column 2, column 3) Values(vaiue 1, value 2, value 3)
Syntax 2: INSERT INTO tablename
Values(value 1, va!ue2, value3)
5) DELETING RECORD :
Syntax 1; DELETE for tablename WHERE Coiumnname =” value ”
Syntax 2; DELETE for tablename
6) MODIFYING RECORD:
Syntax : UPDATE tablename SET column 1= “newvalue” where column 2= value2
7) SORTING RECORD:
Syntax 1 SELECT * FROM TABLENAME ORDER BY COLUMNNAME;
Syntax 2 select * from tablename ORDER BY columnname DESC;
| SQL DDL COMMANDS LIST | |
| Commands | Description |
| CREATE | Used to create database or tables |
| ALTER | Modifies the existing structure of database or table |
| DROP | Deletes a database or table |
| RENAME | Used to rename an existing object in the database |
| TRUNCATE | Used to delete all table records |
| SQL TCL COMMANDS LIST | |
| Commands | Description |
| COMMIT | Permanent save into database |
| ROLLBACK | Restore database to orginal form since the last COMMIT |
| SET TRANSACTION |
SET TRANSACTION command set the transaction properties such as read-write or read-only access |
| SAVE POINT | Use to temporarily save a transaction so that we can rollback to that point whenever required |
| SQL DML COMMANDS LIST | |
| Commands | Description |
| INSERT | Adds new rows into database table. |
| UPDATE | modifies existing data with new data within a table |
| DELETE | Deletes the records from the table |
| SQL DQL COMMANDS LIST | |
| Commands | Description |
| SELECT | Retrieve data from the table |
Part B
Short Answers
Question 1.
Define database?
Answer:
“A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data”.
Question 2.
Define DBMS
Answer:
Definition;
- A database management system (DBMS), is system software for creating and managing databases.
- The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.
Question 3.
Define degree of consistency?
Answer:
To prevent conflict in database updates, the transactions are isolated from other users and serialized. This is also known as the Degree of Consistency.
Question 4.
What are the limitations of the database?
Answer:
- Data Duplication
- High Maintenance
- Security
Question 5.
Write the various forms of the database.
Answer:
- Relational Database Management System (RDBMS)
- And Object Database Management System (ODBMS).
Question 6.
Define relational database?
Answer:
Any database whose logical organization is based on a relational data model is known as Relational Database.
Question 7.
What do you mean by the table in the Relational database model?
Answer:
In relational database model,
- The table is defined as the collection of data organized in terms of rows and columns.
- The table is the simple representation of relations. The true relations cannot have duplicate rows
Question 8.
Write the types of SQL commands.
Answer:
- Data Definition Language (DDL)
- Data Manipulation Language (DML)
- Data Query Language (DQL)
- Transaction Control Language (TCL)
- Data Control Language (DCL)
Question 9.
Define Primary key?
Answer:
- The candidate key that is chosen to perform the identification task is called the primary key and any others are Alternate keys.
- Every tuple must-have, a unique value for its primary key.
Question 10.
What is XAMPP?
Answer:
- XAMPP is a free and open-source package.
- It was developed by Apache.
- It is a software platform for MySQL, PHP and Peri programming languages.
Question 11.
Define Composite key?
Answer:
A key with more than one attribute to identify rows uniquely in a table is called a Composite key. This is also known as Compound Key.
Part C
Explain In Brief Answer.
Question 1.
Explain three database components of the network model?
Answer:
The three database components of Network models are Network schema, Sub schema, and Language.
Network schema – schema defines all about the structure of the database.
Sub schema – controls on views of the database for the user.
Language – basic procedural for accessing the database.
Question 2.
List few commonly used databases.
Answer:
- DB2
- MySQL
- Oracle
- PostgreSQL
- SQLite
- SQL Server
- Sybase
Question 3.
What are the roles of a Database administrator?
Answer:
- Database Administrators (DBA’s) who takes care of configuration, installation, performance, security and data backup.
- DBA’s possess the skills on database design, database queries, RDMS, SQL and networking.
- The primary task is the creation of new user and providing them with access rights.
Question 4.
Define Super key?
Answer:
- An attribute or group of attributes, which is sufficient to distinguish every tuple in the relation from every other one is known as Super Key.
- Each super key is called a candidate key.
- A candidate key is selected from the set of Super Key.
Question 5.
Write a note on MySQL.
Answer:
- The candidate key that is chosen to perform
- MySQL is a database management system founded by Monty Widenius
- MySQL is open-source software that allows managing relational databases.
- It also provides the flexibility of changing the source code as per the needs.
- It runs on multiple platforms like Windows, Linux and is scalable, reliable and fast.
Question 6.
Write a short note on Row (or Record or tuple)
Answer:
- A single entry in a table is called a Row or Record or Tuple.
- Set of related data are represented in a row or tuple.
- The horizontal entity in a table is known as a Record or row.
Question 7.
Give the roles and responsibilities of DBA?
Answer:
Database Administrators (DBA’s) take care of configuration, installation, performance, security, and data backup.
DBA’s possess the skills in database design, database queries, RDMS, SQL, and networking.
The primary task is the creation of new users and providing them with access rights.
Part D
Explain in detail.
Question 1.
Explain the following:
- Primary Key
- Foreign Key
- Candidate Key
- Super Key
- Composite key
Answer:
1. Primary Key:
- This key of the relational table identifies each record in the table in a unique way.
- A primary key which is a combination of more than one attribute is called a composite primary key.
- The candidate key that is chosen to perform the identification task is called the primary key
2. Foreign Key:
- A foreign key is a “copy” of a primary key that has been exported from one relation into another to represent the existence of a relationship between them.
- A foreign key is a copy of the whole of its parent primary key i.e if the primary key is composite, then so is the foreign key.
- Foreign key values do not (usually) have to be unique.
- Foreign keys can also be null.
- A composite foreign key cannot have some attribute(s) null and others non-null.
3. Candidate Key:
- Each super key is called a candidate key.
- A candidate key is selected from the set of Super Key.
- While selecting the candidate key, redundant attributes should not be taken.
- The candidate key is also known as minimal super keys.
4. Super Key:
An attribute or group of attributes, which is sufficient to distinguish every tuple in the relation from every other one is known as Super Key.
5. Composite Key (Compound Key): A key with more than one attribute to identify rows uniquely in a table is called a Composite key. This is also known as Compound Key.
Question 2.
Tabulate the ER diagram notations
Answer:
