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DATA BASE

MANAGEMENT

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INTRODUCTION

Key components of computer system are: Input The processor Storage

Output Data communication

There are two items that add life to the

computer system allow it to become amanagement information system. YesData and Information !!

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DATA and INFORMATION..40,50,45,70,90,130,120,35.

Just Data

Weights (in kgs) of the faculties and staffs of XISS, Ranchi.

We are now somewhere between just data and information.

Now, let us process the data

What is the average weight of the people who will use thelift?

What is the weight of the heaviest faculty/staff who will usethe lift?

We can now, process the original data to give meaningfuland valuable data information.

Management can now able to find out the capacity and

what kind of lift they require to install.

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DATA BASE DATABASE CONTAINS DATA, NOT

INFORMATION.

With some assertions about the meaning of thedata and some rules for processing the data,

we are able to produce information from thedatabase.

Thus, through proper design and use of thedatabase, it can be an essential tool for

producing information for making managementdecisions.

When a organization has a centrally, integratedcollection of logically organized data, it has a

database!!

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DATABASE MANAGEMENT

SYSTEM DBMS is a system or set of rules and methods

that allows for the definition, creation, updating,reading, maintenance, and protection of thedatabase.

Features important in Database management: Speed, process many transaction in a short time Accuracy, firms require the data they store and use to

be correct Good at repetitive work

Hence, the computer has radical impact ondatabase management systems becausecomputer has all these characteristics.

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OBJECTIVES OF DBMS

Provide the mass storage of relevantdata

Make access to the data easy for the

user

Provide prompt response to userrequests for data.

Make the latest modifications to thedatabase available immediately.

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OBJECTIVES OF DBMS

Eliminate redundant data.

Allow multiple users to be active at one

time.

Allow for growth in the database system.

Protect the data from physical harm andunauthorized access.

These are the goals that a DBMS strive to

fulfill.

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STEPS IN DESIGNING A

DATABASE

Determine the purpose of thedatabase

Determine the tables needed

Determine the fields needed

Identify the Primary keys

Determine the relationship betweentables

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DATABASE DESIGN

Conceptual Model of database designprovides a framework whichspecifies, in a systematic manner. It

uses two frameworks:

Entity-relationship model

Normalisation

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Entity-Relationship Model (E-R

Model)

Based on a perception of real world thatconsists of a set of basic objects, calledentities, and a set of relationships among

these objects. E-R Model specifies following elements:

Entity

Relationship

Mapping constraints

E-R Diagram

Reduction of E-R diagram to tables

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Entity: An entity is an object thatexists and is distinguishable fromother objects. It may be physical,

such as a person or a book, or it maybe a concept, such as holiday or ajob.

An entity is represented by a set ofattributes. It is the properties possessedby each member of the entity set.

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Entity

CUSTOMER

Name

Cust_id Address

attributes

entity

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RELATIONSHIP: An association amongseveral entities.

MAPPING CONSTRAINTS:

E-R Model defines certain constraints towhich the contents of a database mustconform. It may be of three types:

Cardinalities: it express the number ofentities to which another entity set canbe associated via a relationship. It canbe of four types: one to one, one tomany, many to one, many to many.

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Existence dependencies: If theexistence of entity A depends on theexistence of entity B, A is said to beexistence-dependent on B. Ex: Account

and Transaction have existencedependencies. If account (B) is closed,transaction (A) has to be closed.

Keys: It specifies how entity andrelationships are distinguished. Ex. PANis the super-key for income taxpurpose. Roll Number is the super-keyfor identifying different students of ainstitution.

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ENTITY - RELATIONSHIP DIAGRAM:

After identifying the various entities, theirattributes, relationships and constraints,

the database designers document theseinto an entity-relationship diagram.

Rectangle represents entity

Ellipses-attributes

Diamonds- Relationship Line- represents link

CUSTOMER

Name

Cust_id Address

Account

balance

Depositor

AccNumber

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REDUCTION OF E-R DIAGRAM TO TABLES

On the basis of E-R diagram, tables are prepared.For each entity set, a table is prepared with the

corresponding name assigned and attributesshown in column.

A similar table is prepared for relationship set.

Cust_id Cust Name Address

A101 AMIT CLUB RD,RANCHI

A102 MOHIT HARMU, RANCHI

A104 PRINCE PURULIA ROAD, RANCHI

CUSTOMER

ACCOUNT

Acc Number Balance

291300000156 10,000

291300000278 23,000

291300000822 16,000

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Cust_id Account Number

A101 291300000156

A102 291300000278

A104 291300000822

DEPOSITOR

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NORMALISATION

Normalization is a process of simplifying therelationships among data elements in a record.During this process, the complex and redundantattributes are simplified and removed.

It helps to: Structure the data

Permit simple retrieval of data in response to query

Simplify the maintenance of data

Reduce the need to restructure or re-organise the datawhen new application requirements arise.

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Normalization Process

The tests (conditions) for normalisationare:

1NF : First Normal Form: Nowconsidered to be part of the formaldefinition of a relational model. It statesthat domain of an attribute must includeonly atomic values.

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Normalization Process 2NF (Second Normalisation Form):

It is based on the concept of full functionaldependency. A functional dependency X Y is afull functional dependency if removal of anyattribute A from X means that the dependencydoes not hold any more, that is for any attribute

A belongs to X, (X-{A}) does not functionallydetermine Y.

An entity is said to be in 2NF if all its columnsdepend on the primary key only.

3NF (Third Normalization Form): Based on transitive dependency. A table qualifies

for 2NF and do not have transitive dependencies.

Each column in a table must be dependent onthe entire primary key, not just part of it.

First Normal Form Example

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DNAME DNUMBER DMGRIDN DLOCATIONS


Sales 5 10051 (Delhi,Mumbai,Banglore)

Administration 1 20061 Delhi

Plant 2 30088 Gurgaon


Sales 5 10051 Delhi,

Sales 5 10051 Mumbai

Sales 5 10051 Banglore

Administration 1 20061 Delhi

Plant 2 30088 Gurgaon

First Normal Form Example

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Example: Project Management

ProjectNo.

ProjectName

EmployeeNo.

EmployeeName

RateCategory

HourlyRate(Rs.)

1055 CIL Survey 11,12,16 Paul,Rahul,Binay

A,B,C 300,250,200

1088 EducationProject 11,17 Paul, Kartik A,B 300,250

1NF: No keys defined and repeating

groups. When we remove groups anddefine the primary key (PK), we are leftwith

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ProjectNo.(PK)

ProjectName

EmployeeNo. (PK)

EmployeeName

RateCategory

HourlyRate(Rs.)

1055 CIL Survey 11 Paul A 300

1055 CIL Survey 12 Rahul B 250

1055 CIL Survey 16 Binay C 200

1088 EducationProject

11 Paul A 300


17 Kartik B 250

2NF: The project name is only dependent on

project number. The employee name,category, rate are dependent on employeenumber. So we remove them and placethese fields in a separate table. So we are

left with

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EmployeeNo.

EmployeeName

RateCategory

Hourly Rate(Rs.)

11 Paul A 300

12 Rahul B 25016 Binay C 200

11 Paul A 300

17 Kartik B 250

ProjectNo.

EmployeeNo.

1055 111055 12

1055 16

1088 11

1088 17

ProjectNo.

ProjectName

1055 CIL Survey


EmployeeTable

ProjectTable

Employee-Project Table

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3NF: Now, only the employee table has morethan one-key attributes. Employee name is not

dependent on either rate category or hourlyrate and same applies to rate category. OnlyHourly rate is dependent on rate category, sowe have to remove this

EmployeeNo.

EmployeeName

RateCategory

11 Paul A

12 Rahul B

16 Binay C

17 Kartik B

RateCategory

HourlyRate

(Rs.)A 300

B 250

C 200

EmployeeTable

Rate Table

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Owner

BName CName

LienOrRegular

Registered_vehicle

CYear

Owns

CAR

Truck TYear

TModel

TMake

TEng_NoCEng_No

CMake

CModel

CAddress

Name

Address

DrvLicNo BAddress

Person

Bank

Company

Purch_Date

U

U

Reg_No

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Recent Trends in Database Because of the development of new trends in

information technology, new trends in databasesystems have also emerged.

In recent years, several new application areas fordatabase systems have emerged that are notserved by relational data model.

Some areas are distributed processing,computer-aided design, multimedia andhypermedia etc.

Moreover, traditional business applications havegrown more complex over time. For example,todays business applications often have to dealwith image data and hypermedia databases.

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Recent Trends in Database

Distributed Database:

The DDBMS emerged as a merger of twotechnology:

Database technology

Network and data communication technology

Tremendous development due to wire andwireless technologies from satellite and

cellular communications.

A DDB is one that is stored in more than onephysical location. Parts of the database arestored physically in one location and other partsare maintained in other locations.

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Object Oriented Database:

OOPLs: It creates software programs byselecting and arranging objects rather than bywriting program code.

When you integrate database capabilities withobject programming language capabilities, theresult is an object-oriented databasemanagement system or OODBMS

OODB is proposed to meet the needs of thesemore complex applications.

The object typically has two components state

(value) and behavior (operations)

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Hypermedia Database:

Also referred as multimedia or hypertext,

includes various media, such as text, graphics,audio and video alongwith procedure for theiruse.

In hypermedia databases, the concept ofdistributed information systems is used whichhas led to the emergence of global internet.

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Management Responsibility

Management must understand some ofthe terms related to DBMS, concepts &approaches

Manager to participate intelligently

User needs a facility for asking DBMSfor information and reports

Success of database also depends on

user acceptance

Documents

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