Network Model in DBMS

Network model in DBMS 

  • In 1970s CODASYL (conference on data system language) introduced a network model which is an extension to the hierarchical model but the difference is that the network model uses many to many rather than one to many.
  • In 1970 IBM introduced IDMS(information data management system), a product based on the network data model.

 

Network data model 

  • Data Organisation in the network model is just like a graph rather than a tree, a child record can have any number of parent records 
  • This was the most widely used model before the relational database model was introduced
Network Model in DBMS

Features of the network data model

  • It was introduced to overcome the drawbacks of the hierarchical model because the hierarchical model uses one to many relationship as a result only a few relationships can be established. 
  • Many to many relationships: But here in network model It uses many to many relationship where the child only is allowed to have more than one parent node as a result large number of relationships can be applied with different data tables and data access becomes easier and faster .

 

Example for or network data model 

  • Consider two tables “employee” table and “date of joining” table with the help of this network model more than one employee record can be linked to 2 more than and one record in the “date of joining” table
  • For example, as shown in the figure both admin and HR uses the same data row present in the date of joining table i.e [2014] as a result data duplicate is reduced .

 

Advantages of the network model 

As more number of relationships or established between data tables it reduces data duplicity saves memory improve access time of data.