Network Model

A network database is similar to a hierarchical database except that each record can have more than one parent, thus creating a many-to-many relationship among the records (See Fig. 6). For example, a customer may be called on by more than one salesperson in the same company, and a single salesperson may call on more than one customer. Within this structure, any record can be related to any other data element.

Fig. 6. Network data relationships.

The main advantage of a network database is its ability to handle relationships among various records. Therefore, more than one path can lead to a desired data level. The network database structure is more versatile and flexible than is the hierarchical structure because the route to data is not necessarily downward; it can be in any direction.

In both the network structure and the hierarchical structure, data access is fast because the data path is predefined. However, any relationship between data items must be defined when the database is being created. If a user wants to retrieve or manipulate data in a manner not defined when the database was originally created, it is costly and time-consuming to redesign the database structure. This limitation led to the development of the relational database model.