Database Model

A Database model defines the logical design of data. The model describes the relationships between different parts of the data. In history of database design, three models have been in use.

Hierarchical Model

In this model each entity has only one parent but can have several children . At the top of hierarchy there is only one entity which is called Root.

Hierarchical Model of database

Network Model

In the network model, entities are organised in a graph,in which some entities can be accessed through sveral path

Network Model of database

Relational Model

In this model, data is organised in two-dimesional tables called relations. The tables or relation are related to each other.

Relational Model of database