Database
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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
  • Network Model
  • Relational Model

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