The network model is a flexible way of representing entities and their relationships. This model forms a graph in which entities are nodes and relationship types are the connecting edges.
The network model allows a more natural modeling of relationships between entities. Here one entity can be related to multiple other entities. Relationship cycles are also permitted.
Network Database :
A network database consists of a collection of records connected to one another through links. A record is similar to an entity in the E-R model in many respects. Each record is a collection of fields (attributes), each of which contains only one data value. A link is an association between precisely two records. Thus, a link can be viewed as a restricted form of relationship in the sense of the E-R model.
Data Structure Diagram :
A data-structure diagram is a schema representing the design of a network database. Such a diagram consists of two basic components: 1. Boxes, which correspond to record types 2. Lines, which correspond to links A data-structure diagram serves the same purpose as an E-R diagram; namely, it specifies the overall logical structure of the database. So that you will understand how such diagrams are structured, we shall show how to transform E-R diagrams into their corresponding data-structure diagrams.