This presentation provides an overview of database management systems. It discusses what a database and DBMS are, and covers data models like relational, network, and hierarchical. It also discusses database concepts like data abstraction, views, keys, and advantages of using a DBMS like data independence and sharing data. The goal is to explain core DBMS concepts at a high level.

1. A Presentation
on
Database Management
System

2. Content
• Data, Database and Database Management System
• Purpose of Database Management System
• Concept of Data Abstraction
• Data Models
• Views and Different types of Keys in Relational Model
• References

3. DATABASE : A collection of data is referred to as
database.
e.g. 1. record of students stored in files
2. information stored over internet
DATABASE MANAGEMENT SYSTEM: It is basically a
computer based record keeping system (program).
e.g. MySQL
Microsoft Access
FileMaker
FoxPro

4. Purpose of database :
1. It reduces DATA REDUNDANCY to a large extent.
2. It controls DATA INCONSISTENCY.
3. It facilitate SHARING of data.
4. It ensures DATA SECURITY.
Name D.O.B Fees
Harsh 23/01/1993 Not paid
Amar 04/11/1994 Paid
Devendra 14/06/1992 Not paid
Harsh 23/01/1993 Not paid
Name D.O.B Fees
Harsh 23/01/1993 Paid
Amar 04/11/1994 Paid
Devendra 14/06/1992 Paid
Harsh 23/01/1993 Not paid
Data Redundancy Data Inconsistency

5. Three levels of database implementation (concept of abstraction)
1. INTERNAL LEVEL (PHYSICAL LEVEL):
It describes how data are actually stored on the storage medium.
It is closest to database programmer.
Lowest level of database abstraction.
2. CONCEPTUAL LEVEL:
It describes what data are actually stored in database.
It is closest to the database manager.
It is an intermediate level of database abstraction.
3. EXTERNAL LEVEL (VIEW LEVEL):
It describes the way in which the data are viewed by individual user.
It is the level closest to the users.
It is the highest level of database abstraction.

6. Three levels of data abstraction
View 1 View 2 View 3
Conceptual
level
Physical
level
External level
Internal
Stored-acc. length=60
Account # type=bytes(15) offset=0
Name type=bytes(20) offset=15
Type type=bytes(10) offset=35
Amount type=bytes(15) offset=45
Conceptual
AC_No numeric(15)
AC_Name character(20)
Type character(10)
Amount numeric(15)
View 1
AC_Name
Amount
View 2
AC_No
AC_Name
Type
Amount
Account holder Manager
(DBMS Programmer)
Database
handler
User

7. Item # Item-
name
Price
I1 Cake 50.00
I2 Bread 9.00
I3 Biscuits 6.00
I4 Snacks 16.00
1.Relational Data Model
Supp# Supp-name
S1 Britannia
S2 New Bakers
Supp# Item# Qty-
Supplied
S1 I2 20
S1 I3 25
S1 I4 10
S2 I1 5
S2 I3 10
Table : Items
Table : Suppliers
Table : Shipments
1. RELATIONAL DATA MODEL: In relational data model, the data is stored in
the form of tables (i.e. rows ad columns).
These tables are called relations.
The user of the relational database system may insert new tuples, delete tuples,
and modify tuples.
DATA MODELS

8. S1 Britannia
20 25 10
I2 Bread 9.00 I3 Biscuit
s
6.00 I4 Snacks 16.00
2. Network Data Model
2. NETWORK DATA MODEL: The network data model differs from the
relational model.
In this model data is represented by connection of records and relationships
among data are represented by links.
Records are organized as graphs.

9. S1 Britannia
20
25
10
I2 Bread 9.00
I3 Biscuits 6.00
I4 Snacks 16.00
3. Hierarchical Data Model
3. HIERARCHICAL DATA MODEL: Data is represented by collection of records
and relationships among data by links, similar to the network model.
Records are organized as trees rather than graphs.
Represents relationship among its records through parent child relationships.

10. The relational model was put forward by E.F. Codd of the IBM.
It is considered as a very important concept in DBMS.
Some basic terminologies:-
Relation : A relation is a table i.e. data is arranged in rows and columns.
Tuple : The rows of tables are generally referred to as tuples.
Attributes : The columns of tables are generally referred to as attributes.
Degree : The number of attributes in a relation determine the degree of the relation.
Cardinality : The number of tuples in a relation is called the cardinality of the
relation.
Relational Data Model

11. Views
A view is a (virtual) table that does not really exist in its own right but is instead derived
from one or more underlying base tables.
It is an excellent way to give people access to some but not all information (data
abstraction).
Database Keys are used to establish and identify relations between tables.
Primary key: It is a set of one or more attributes that can uniquely identify the tuples
within the relation.
Candidate key : All attribute combinations inside a relation that can serve as a primary
key are candidate keys.
Alternate key: A candidate key that is not the primary key is called the alternate key.
Foreign key : A foreign key is a non key attribute whose value is derived from the
primary key of another table.

12. Empno Name D.O.B. Post Area_code
101 Aakash 13/03/1994 Director 221
102 Shahrukh 26/11/1993 Director 223
103 Nishank 30/02/1989 Manager 156
104 Shivesh 24/03/1993 Clerk 223
105 Prem 31/05/1992 Clerk 156
Area_code Area State
156 Mumbai Maharashtra
221 Bengaluru Karnataka
223 Pune Maharashtra
Table : Location
Table : Employee
Primary Key in
this table
Foreign key in
this table
Primary Key in
this table

13. Advantages of Database Management System
1. Self describing nature of Database System:-
A database management system catalogue stores the descriptions of the database
and this description is called Metadata, which describes the Structure of Database.
2. Insulation between Program and Data (Data Independence):-
DBMS provides the insulation between program and data called as program data
Independence which allows changing data storage structure and operation without having
to change the DBMS access program.
3. Data Abstraction:-
Data Models is used to hide storage details and present the user with a conceptual
view of Database that does not include many of the details of how data is stored.
4. Sharing of Data and Multiple User Transaction processing:-
DBMS allows a set of concurrent users to retrieve and to update the Database.
5. Support of Multiple Views of the Database

14. References
• http://patentimage.storage.googleapis.com
• www.tutorialspoint.com/Database_management_system.htm
• https://en.m.Wikipedia.org/wiki/dbms.html