Saturday, 1 March 2014

Data models and their types | database managenent system


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.

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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