Saturday 1 March 2014

Data models and their types | database managenent system


DATA MODELS

INTRODUCTION:-
It can be  defined as an integrated collection of concepts for describing and manipulating data,relationship between data and the constrains of the data in any organization.
It consists of three components:-
1.)Structured part:- It consist of set of rules according to which database can be connected.
2.) Manipulative part:- It defines the types of operations that are allowed on data.
3.) Set of integrity rules:-It ensures that the data is accurate.

PURPOSE OF DATA MODEL:- Purpose of data model is to represent the data and to make it understandable.

TYPES OF DATA MODEL:-
There are 3 types of data models:-
1.) Object based data models
2.) Physical data models
3.) Record based

1.) OBJECT BASED DATA MODELS:-It uses the concepts such as entities,attributes and relationship.It is of further 4 types:-
1.) ER(entity relationship)model
2.) Object oriented ER model
3.) Semantic model
4.) Functional model

2.) PHYSICAL DATA MODEL:-It describes how the data is stored in the computer representing the information such as record structure ,record modeling and access paths.

3.) RECORD BASED DATA MODEL:- These are used in describing the data at logical and view levels.These are used to specify the overall logical structure of the database.Record database models are of 3 types which are:-
1.) Hierarchical model
2.) Network model
3.) Relational model

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