This document provides an introduction to database management systems (DBMS). It discusses that a DBMS is a collection of data and software programs used to store and retrieve large amounts of data. The key purposes of a DBMS are to organize data, store and transform data into information to support decision making. It also describes three levels of data abstraction (physical, logical, and view levels) and several common database models, including hierarchical, network, relational, object, and entity-relationship models.

1. Database management
system
Presented By :
Rishi Ram Khanal
BIM 4th Semester (TU)
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2. Content
• Introduction to DBMS
• Purpose of DBMS
• Data abstraction
• Database model
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3. Introduction
• DBMS stand for database management
system.
• Database is a collection of data and
management system.
• It is a set of programs to store and retrieve
data .
• This system is basically developed for large
.amount of data .
• There are two things required optimization
store of data and retrieval of data.
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4. Purpose
• It is a software tool that makes it possible to
organize data in data base .
• To store and transform data into information
to support making decision .
there are three type of main purpose of
DBMS
The physical database: the collection of files
that contains the data .
The database engine : the software that
makes it possible to access and modify the
contents of the database .
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5. The database scheme: the specification of
the logical structure of the data stored in
the database.
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6. Data abstraction
• It hides complexity of data .
• It hides unnecessary data and function .
There are three level of data abstraction
• Physical level :The lowest level
abstraction describe how the data are
actually stored
• The physical level describe complex low-
level data structures in detail .
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7. Logical level : this level of abstraction
describe what data are stored in the data
base .
• what relationship exist among those data .
View level
• It is the highest level of data abstraction
• view level describe only part of the entire
database
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8. • view level describes the user interaction
with database system.
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9. Data base model
Hierarchical Model
• They build upon individual data sets and
are able to express hierarchical or network
like structures of the real world
• The data is stored as records which are
connected to one another through links.
• A record is a collection of fields, with each
field containing only one value
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10. • The hierarchical database model
mandates that each child record has only
one parent, whereas each parent record
can have one or more child record
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11. Network level
• The network model expands upon the
hierarchical structure, allowing many-to-
many relationships in a tree-like structure
that allows multiple parents.
• The network model organizes data using
two fundamental concepts,
called records and sets
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13. Relational model
The data is stored in two-dimensional tables
(rows and columns). The data is
manipulated based on the relational theory
of mathematics.
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14. • The object model
• the data is stored in the form of objects,
which are structures called classes that
display the data within. The fields are
instances of these classes
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15. ER model
• The ER model defines the conceptual view
of a database.
• It works around real-world entities and the
associations among them.
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