NETWORK DATABASE MODEL
The network database model was invented by Charles Bachman in 1969 as an enhancement of the already existing database model, the hierarchical database model.Anetwork database model is adata model which uses graph structure with pointers to represent relationship. The graph structures are similar to tree structures in terms of links or pointers but they include cycles. The record structure of network model is based on graph and the relationships are based on pointers or links.
FEATURES OF NETWORK DATABASE MODEL:
- It can represent redundancy in data more efficiently than that in the hierarchical model.
- There can be more than one path fromaprevious node to successor node/s.
- The operations of the network model are maintained by indexing structure of linked list (circular) whereaprogram maintainsacurrent position and navigates from one record to another by following the relationships in which the record participates.
- Records can also be located by supplying key values.
ADVANTAGES OF NETWORK DATABASE MODEL:
- Simple Concept: Similar to the hierarchical model, this model is simple and the implementation is effortless.
- Ability to Manage More Relationship Types: The network model has the ability to manage one-to-one (1:1) as well as many-to-many (N: N) relationships.
- Easy Access to Data: Accessing the data is simpler when compared to the hierarchical model.
- Data Integrity: Inanetwork model, there's alwaysaconnection between the parent and the child segments because it depends on the parent-child relationship.
- Data Independence: Data independence is better in network models as opposed to the hierarchical models.
DISADVANTAGES OF NETWORK DATABASE MODEL:
- System Complexity:Navigational data access mechanism makes the system implementation more complex. Database administrator, database designer, programmers and even end users should be familiar with the internal data structure in order to access data.
- Absence of structural independence:Updating inside this database isatedious task. One cannot changeaset structure without affecting the application programs that use this structure to navigate througb the data. If you changeaset structure, you must also modify all references made from within the application program to that structure.