dbms assignment final

8/2/2019 DBMS Assignment Final

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Database EnvironmentIntroduction-A DBMS is a data storage and retrieval system which permits datato be stored non-redundantly while making it appear to the user as if the data is well-

integrated Store, retrieve and manipulate data.

Wide Information system.

Characteristics of the information

Dynamic and time dependent,

Various sources Enlarged

Range of database application

Personal data.

Workgroup database.

Departmental database.

Enterprise database.

There are many different types of Database systems; which are

Oracle

DB2

MS Access

Sybase

My SQL

Definitions-

Data: Known facts that could be stored on the computer media like; text graphics, videos,

sounds etc.

Database: It is the organized collection of logically related data.

Met data: Data that describes the characteristic of other data.


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Information: Data processed to be in useful decision making.

File System vs. DBMS-

Traditional File System:

File system was developed to store data. It is also used today. And the other thing is it

helps to understand database system. It is specially used to backup some of the database

system. But there are many disadvantages in the file system. Below is the list of some of

the disadvantages of this file system.

Long development time: File system takes very long to develop the application. And

there is very less opportunity to use the previous development efforts.

Limited data sharing facility: There is very little opportunity to share data with other

application.

Duplication of data: Wasteful, loss of metdata integrity.

Excessive data maintenance: The factors above show that the file system takes too

heavy program maintenance load.

Database Approach:

A Database management System is a data storage and recovery system which permits data

to be stored non-redundantly. DBMS is a large, integrated collection of data describing

activities of any company or organizations. Below are the some properties of the DBMS;

DATA is integrated, shared, self-described and constant.

Different users need different kind of information and DBMS allows different type of

data views to different users.

DATA is self-determination in DBMS


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Some of the Advantages of the Database management system;

Negligible data Redundancy.

Improved data sharing.

Improved data quality.

Improved data quality.

Data accessibility and responsiveness.

Increased security.

Enforcement standards.

Less data maintenance.

Increased productivity of data application.

Backup/Recovery and data concurrency are accessible in DBMS.

Components of Database Environment-

1. CASE tools: These are the Computer Aided Software Engineering tools; they are

used to design database and applications.

2. Met data: Data that describes the properties or Characteristics of the other data. It

includes data definition, data structures and rules or constrains. And the other thing

is met data describes data it does not include data.

3. Repository: It is an extended set of metadata for managing databases and other

components of the information system. In other words we can say it is thecentralized storehouse of metadata.

4. Database: An organized collection of logically related data. Or we can say it is an

illustration of a collection of related data.


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5. Software: Data definition and data manipulation (DBMS) are the Software that is

used to define, create, maintain and provide authorized access to the database and

the store-house of it.

6. User Interface: languages, menus etc by which users interact with the other system

applications.

Different types of database users-

1. Database administrator (DBAs)

Database Administrators are intended to

Installing and upgrading the application tools and database server.

Manage resources for data. Allocating system storage and planning future storage requirements for the database

system

Creating primary database storage structures.

Creating primary objects like tables, views, indexes etc.

Controlling and monitoring user access to the database.

Backing up and restoring the database

2. Database Designer

Database designers are deliberated to

Prepare database formation for application.

Design and develop database application.

Estimating storage requirements for an application.

Tuning the application during development.

Establishing security measures for an application during development.

3. Application Programmer

Application Programmers are intended to

Develop and Implement requirements of end users.

Interact with system through Data manipulation language.


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4. End user

End users are anticipated to

Use the application and database.

Entering, modifying, and deleting data, where they are allowed to.

Generating reports from database.

Functionality provided by DBMS

Views

Security

Concurrency

Integrity

Back up/Recovery

Design

Different t es of Com onents and users of


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Easy update.

1. Views:

Database management system has a facility of custom representation of data that

correspond to the need of the class of the user. It provides representation of data for

the different users to protect data quality.

There are three kinds of views available in DBMS.

1) Logical: User views (queries)

2) Conceptual: Database administrators model for data( E-R diagrams)

3) Physical: Actual Data structure(SQL statements)

2. Security

DBMS has some components that Limits data access to properly authorized users or

programs and Protect data against accidental or intentional damage.

3. Concurrency:

There are some functions that prevent two users from interfering with each other

when they use the same information.

4. Integrity:

This function protects the relationship among different related records in the database.

5. Back up and recovery:

This function processes to confirm and repeat the transaction so that we can recover

the database after a problem.

But this recovered database may be slow and it may provide us different result from

the original at some times.

Backu + Transa =Recovered


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6. Easy update:

Updating the database is very easy in the database management system.

DBMS in Commercial and Non Commercial ways

DBMS is currently used by different users in commercial and non commercial environment.

They use DBM system to maintain their data records in proper way. Different type of

database management system can be structured according to there environment of using

database.

Database in non-commercial environment:They use databases to in non-commercial ways means they are not related to commercial.

Following are the examples of non-commercial environment.

1. Universities:

They use DBMS to maintain information of the students, results, working staff, lectures,

etc.

2. Hospitals:

In both government and private hospitals they use DBM system to keep the data of their

patients, doctors, other staffs, surgery times etc. By using this system in hospitals they can

serve their patients very easily like they can easily access the previous medical treatment

of the patient and decide how to treat them.

Database in commercial environment:

They use the DBM system to keep the commercial record of their company. Bellow is the

examples of the commercial environment.

1. Manufacturing company:

They use the suitable DBM system to store the information of the items that they

produced information of the employ, the bills, income, etc.


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2. Banking:

Bank is the most important place when we talk about the commercial environment. They

use different types of database in bank. They use database to store the information like

accounts, transaction, withdrawal, loans, mortgages etc.

3. Airlines:

They uses the system to store all the information about the tickets, passengers, luggage,

food, employs etc.

4. Telephone exchange:

They use the DBM system to store all the detail of calls, numbers, billings, call charges etc.

DBMS haS MaDe thiS all organizationS work so easy and fast. So DBM

system is very important in all the commercial and non commercial

environments.

Fast-track train OrganizationBelow are the snapshots of the database of the fast track train organization.I have taken

Trn for Train no, Cti for Customer Id and RSN for Reservation no. I have

considered three trains for example in for this organization and five reservations in one

train.

We need to normalize our database. If we dont normalize the database there can be data

redundancy or data duplication.

Train

no

Train

orig

Train

dest

Dept

time

Arr

time

Train

model

Train

cap

Empl

ID

Emp

role

Emp

name

Cust

no

Cust

name

Cont

no

Cust

add

Cost Pay

meth

Resr

no


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1st

Normal Form

Step-1: eliminate all the repeating groups

Step-2: find a composite primary key.

Primary key: Train no, Employee no, Customer ID

Step-3: Identify all the dependencies

Train no -> train origin city, Train Destination, Train departure time, Arrival time

Train ID -> Model No, Train capacity

Employee ID -> Emp name, Emp role, Emp contact no

Customer ID -> Reservation no, cust name, cust contact, travelling date, payment method

First of all this is the example of data that is without normalization progress. If we create

data without normalization process that will create the duplication of data.

2nd

Normal Form

Step-1: Identify all the key component.

Train number, Employee ID, Customer ID

Step-2: Identify all the dependent attributes.

Train table:

Train Number Train origin Train

destination

Train departure

time

Train arrival

time

Primary key: Train number

Functional dependency:

All the attributes are functionally dependent on the primary key

Employee table:

Emp no Emp role Emp name Contact no

Primary key: Emp no

Functional dependencies:

Emp no -> emp role, emp name, contact no

Transitive dependencies:

Emp name -> Emp role, Contact no

Train info table:


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Train ID Model no Train capacity

Primary key: Train ID

Functional dependencies: all the attributes are functional dependent on primary key.

Cust- reservation table:

Cust ID Resr no Train ID Cust

name

Journey

date

Cost Pay

method

Primary key: customer ID

Functional dependencies:

Cust ID -> Cust name, Cust contact, Travel date, cost, pay method

Transitive Dependencies:

Name -> Cust contact, Pay method, travel date.

3rd

Normal form

Train table:

Train no Train origin city Train dept city Train depr time Train arr time

Primary key: Train number

Functional dependency:

All the attributes are functionally dependent on the primary key

Employee table:

Emp ID Emp name

Primary key: Emp ID

Emp Info table:

Emp name Emp role Contact no

Primary key: Emp name

Functional dependencies: all the attributes are functionally dependent on primary key.

Train info table:

Train no Train model Train capacity

Primary key: Train no



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Cust Journey table:

Cust Id Cust name

Primary key: Cust ID

Cust Info table:

Cust name Travel date Cost Pay method Contact no

Primary key: Cust name


Cust Train Table:

Cust ID Train No Reservation No

Primary key: Customer ID


The database shown above has no repeating groups. And as the database isnormalized till 3rd normal form there is no chance of data duplication or data

redundancy. So we can put this database in action. After making this database I

found it working properly and there is no data duplication. All the screen-shots

are shown below:

Un-normalized data (1)

If we try to publish the data in this format MS-Access will not allow us to go ahead it will

again and again give us the notification as above:


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Un-Normalized data (2)

So we need to normalize the data up-to minimum of third normal form. Steps to normalize

the data are described in the presentation slides below.

Table 1: Train


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Table 2: Customer Id


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Table 3: Customer Info


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Table 4: Customer journey info


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Table 5: Reservation Train


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Table 6: Emp info


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Table 7: Emp Idtrain origin city da

Table 8: Train info


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Table 9: Customer Reservation Table

Below are the some outputs of Queries I have taken questions, SQL output screens and their Design views

as well.

Question 1: Find out the customers travelling in the train Trn1 with their reservation no and contact no

Ans; output screen


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Design view:


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Question 2: Find out the full detail of customer whose reservation no is RSN1

Ans: Output screen


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Design view:we have given the criteria of RSN1 in the customer reservation table so we have received the

information of the customer whose reservation no is RSN1


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How to design a database?

Below are the snapshots of the how to design a database?


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References:

2.Relational database design clearly explained, (Jan L. Harrington),

2002

3.Database design, (Toby J Teorey, Stephen Buxton, Lowell Fryman,

Terry Halpin), 2009

4.Logical Database design Principles, (John Garmany, Jeff Walker, Terry

Clark), 2005

dbms assignment final

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