Saturday, 1 March 2014

Network model and their Advantages and Disadvantages | Data models


NETWORK MODEL

INTRODUCTION-
The network model is a database model conceived as a flexible way of representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice.
The network model replaces the hierarchical model with a graph thus allowing more general connections among the nodes.The main difference of the network model from the hierarchical model is its ability to handle many to many relationships.In other words it allow a record to have more than one parent.
EXAMPLE-



ADVANTAGES OF NETWORK MODEL-
The major advantage of network model are-
1.) Conceptual simplicity-Just like the hierarchical model,the network model is also conceptually simple and easy to design.
2.) Capability to handle more relationship types-The network model can handle the one to many and many to many relationships which is real help in modeling the real life situations.
3.) Ease of data access-The data access is easier and flexible than the hierarchical model.
4.) Data integrity- The network model does not allow a member to exist without an owner.
5.) Data independence- The network model is better than the hierarchical model in isolating the programs from the complex physical storage details.
6.) Database standards

DIS-ADVANTAGE OF NETWORK MODEL-
1.) System complexity- All the records are maintained using pointers and hence the whole database structure becomes very complex.

2.) Operational Anomalies- The insertion,deletion and updating operations of any record require large number of pointers adjustments.
3.) Absence of structural independence-structural changes to the database is very difficult.

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