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
- Network Model
- Relational 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.
In the network model, entities are organised in a graph,in which some entities can be accessed through sveral path
In this model, data is organised in two-dimesional tables called relations. The tables or relation are related to each other.