Database Model:




A database model is the set of rules or the standards that gives the definition that how the database will organize the data. A database model also defines that how the users can view the organization of the data.




Types of Database models

There are three types of a database model. These models are as follows:

Hierarchical Model

The hierarchical model arranges the records in hierarchy such as an organizational chart. In this each of the record is known as a node or a segment. The node is used to represent a particular entity and the node that is on the top is called root. Each node is the subordinate of the node that is on the next higher level.

A higher level node can also be called the parent node and the low level node can also be called the child node. The parent node can consists of one or more than one child nodes. But the child node can only have one parent node. This type of structure can also be called as the inverted tree.


hierarchical-model



Network Model

The network model is just like the hierarchical model. The only difference is that the child node in the network model may have one or more than one parent nodes. The child node in the network model is represented by arrows. This model requires a complex diagram to represent the database. The network model is more flexible than the hierarchical model.


network-model

Relational Model

The relational model is the most commonly used database model. The relational model is considered to be as the more flexible model than the network model and the hierarchical model.




The relational model has simple relations. The relation is defined as a term that is used for table. The relation represents a particular entity. The relation is used to store a particular entity. The relationships are based on the data of the entities. The relationship between the entities is represented by the following diagram:

 

relational-model