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In many ways, the Network Database model
was designed to solve some of the more serious problems with the
Hierarchical Database Model. Specifically, the Network model
solves the problem of data redundancy by representing relationships
in terms of sets rather than hierarchy. The model had its
origins in the Conference on Data Systems Languages (CODASYL)
which had created the Data Base Task Group to explore and design
a method to replace the hierarchical model.
The network model is very similar to the
hierarchical model actually. In fact, the hierarchical model is
a subset of the network model. However, instead of using a
single-parent tree hierarchy, the network model
uses set theory to provide a tree-like hierarchy with the
exception that child tables were allowed to have more than one
parent. This allowed the network model to support many-to-many
relationships
Visually, a Network Database looks like a hierarchcal
Database in that you can see it as a type of tree. However, in the
case of a Network Database, the look is more like several trees which share
branches. Thus, children can have multiple parents
and parents can have multiple children.
![[Network Diagram]](Images/network.gif)
Nevertheless, though it was a dramatic
improvement, the network model was far from perfect. Most
profoundly, the model was difficult to implement and maintain.
Most implementations of the network model were used by computer
programmers rather than real users. What was needed was a simple
model which could be used by real end users to solve real
problems.
Enter the Relational Database Model
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