Data Models In Database Management System

All Data models in DBMS

Overview

• Data

• Information

• Database

• Data Model

Types of Data Model

1. Record Base model

• Relationship model

• Network Model

• Hierarchical Model

2.Entity Relationship Model

3.Object-Oriented Model

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A data is known as the row fact which is stored incomputers memory and used by the user as theoutput.

Example-21.

Data

InformationCollection of data its called information.

Example-House no 21C-S-1,Sch No 78 Indore

DatabaseA collection of inter related data its called database.

Data Model A data model is a collection of concepts thatcan be used to describe the structure of adatabase.

Types of Data Models

1.Record Base model

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Types of Data Models

1.Record Base model • A record based data modelis used to specify the overalllogical structure of thedatabase.

• Each record type defines afixed no. of fields having afixed length.

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Relational model

• In the relational model, data is

organized in two-dimensional tablescalled relations.

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Relations

No Course-Name Unit

CIS15 Intro to C 5

CIS17 Intro to Java 5

CIS19 UNIX 4

CIS51 Networking 5

Attributes

Tuples

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• Attributes.

Each column in a relation is called an attribute.

Relations

• Tuples

Each row in a relation is called a tuple. Atuple defines a collection of attribute values.

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Network ModelIn the network model, the entities are

organized in a graph, in which some entitiescan be accessed through several paths

No Name ID Name Course

No Name Unit ID Name

DEPARTMENT

COURSES

STUDENTS

PROFESSORS

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Hierarchical Model

The hierarchical data model organizesdata in a tree structure

PROFESSORS

No Name

ID Name CourseNo Name Unit

ID Name

DEPARTMENT

COURSES STUDENTS

Hierarchical Model

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2.Entity Relationship Model

• The E-R (entity-relationship) data model views the real world as a set of basic objects (entities) and relationshipsamong these objects

ER Model Basics•Entity•Entity Set•Attributes•Relationship

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Entity

• entity is a thing in the real world with an independent existance. and entity set is collection or set all entities of a particular entity type at any point of time.

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