DBMS consists of a group of programs that manipulate the database

and provide interface between the user of the database and other

application programs

It is collection of programs that enables the users to store , modify

and extract the information from a data base as per the user’s

requirements efficiently and effectively.

Data Base Name COMPANY

MS ACCESS MICROSOFT

ORACLE ORACLE COMPANY

MY SQL ORACLE COMPANY

DB2 IBM

SYBASE

SQL LITE OPEN SOURCE

SQL SERVER 2005 MICROSOFT

Lect. Rahul Gaba (DBU) 6

ID PASSWORD

abc@gmail.com 12345

skilsesplorer@gmail.com 32165

studyiq@gmail.com 678901111

IF login valid, Then navigate to

14.7

DATABASE MANAGEMENT SYSTEMS

A DBMS is a combination of five components: hardware,

software, data, users and procedures

DBMS components

14.8

Hardware

The hardware is the physical computer system that allows

access to data.

Software

The software is the actual program that allows users to

access, maintain and update data. In addition, the software

controls which user can access which parts of the data in the

database.

Confidentiality

The data in a database is stored physically on the storage

devices. In a database, data is a separate entity from the

software that accesses it.

14.9

Users

In a DBMS, the term users has a broad meaning. We can

divide users into two categories: end users and application

programs.

Procedures

The last component of a DBMS is a set of procedures or

rules that should be clearly defined and followed by the users

of the database.

Lect. Rahul Gaba (DBU) 10

14.11

External level

In this level we decide what data is to be represented. This level describes which part of database that is relevant to each users.

It is very close to end user.

A user can create more than one view accordingly to their

requirements.

A view contains only whose portion of database which

are concerned to user. There for some database has different views for different

user.

Lect. Rahul Gaba (DBU) 13

External Level View 1(1(Account User) Required values Saving Account Current Account Mini statement Bill Payment

External Level View 2(Account office User) Required values Saving Account Current Account

Conceptual Level Field Name Data Type Saving Account varchar(16) Current Account varchar2(15) Bill Payment Number(15)

Internal Level Stored Item Length Saving Account Type=byte(16) Current Account Type =byte16) Bill Payment Type = byte(16) Mini satement

14.14

Conceptual level This is the middle level in the three level architecture. This level describes what data is

to be stored.

This level contains logical structure of entire database. This is designed by DBA(Data base Administrator).

Entities( Table):- An entity is object whose information is to be stored in the database.

for example:- In student record student id entity.

Attributes(Fields):- An attributes is a characteristic of interest about an entity, for i.e Roll No, class, name, address, Phone no. are the attributes of entity student.

Lect. Rahul Gaba (DBU) 15

Account Number

Name Age Address BALANCE

1 ANAND 25 144 GREEN 30000

2 RAVI 23 PREET VIHAR

40000

3 AJAY 32 NABHA 50000

The conceptual level must not contain any storage dependent detail . This is also known as logical level.

Row-1

Row-2

Row-3

Cardinality of Table is 3

Degree of Table is 5 Attribute or Field

14.16

Internal level The internal level determines where data is actually stored on the

storage devices.

The internal level interacts directly with the hardware.

The internal level concerned with such things:-

Storage space allocated for data.

Record description for storage.

Record placement.

Data compression and encryption techniques.

A Data Model is a collection of concepts that can be used to describe the structure of a database

IBPS

RRB PO

RRB CLERK-1

RRB CLERK-2

IBPS PO

IBPS-CLERK

The hierarchical data model organize data in a tree structure.

Relationship One to One Parent : Child One to Many Boss : Employees

In a network data model, entities are organized in a graph, in which some entities can be accessed through several paths

Relational data model is the primary model, which is a combination of different relations or tables.

In a relation model, data is organized in two dimensional tables called relation.

An Example of a Table

Records

Fields

Name GatorLink Phone College

Graff rgraff 392-3900 Pharmacy

Harris bharris 392-5555 Medicine

Ipswich zipswich 846-5656 PHHP

Courses Math Reasoning English G.K Computer

IBPS PO 40 40 40 40 40

IBPS CLERK

40 40 40 40 40

RRB PO 50 50 40 40 20

RRB CLERK

50 50 40 40 20

Relational data model is the primary model, which is a combination of different relations or tables.

In a relation model, data is organized in two dimensional tables called relation.

Record

Courses Math Reasoning English G.K Computer

IBPS PO 40 40 40 40 40

IBPS CLERK

40 40 40 40 40

RRB PO 50 50 40 40 20

RRB CLERK

50 50 40 40 20

Table:-- 1. A table has rows and columns, also known as relation. where rows represents records and columns represent the attribute or field.

Row-1

Row-2

Row-3

Row-4

Tuple of relation

Cardinality of Table is 4

Degree of Table is 5

Connectivity of a relationship describes relationship between two or more tables

One to One(1:1)

One to Many(1:M)

Many to One(M:1)

Many to Many(M:M)

Teacher Students Teaching

One : Many

Students Skills Explorer Teaching

One : Many

Supplier Product Teaching

Many : Many