Hierarchical Model

Hierarchical Model


Organizes data in a tree structure.

This structure implies that a record can have repeating information, generally in the child data segments.

Collects all the instances of a specific record together as a record type.

To create links between these record types, the hierarchical model uses Parent Child Relationships. These are a 1:N mapping between record types.

Hierarchical Model


ADVANTAGES:

Hierarchical Model is simple to construct and operate on

Corresponds to a number of natural hierarchically organized domains -e.g., assemblies in manufacturing, personnel organization in companies

Language is simple; uses constructs like GET, GET UNIQUE, GET NEXT, GET NEXT WITHIN PARENT etc.

DISADVANTAGES:

Navigational and procedural nature of processing

Database is visualized as a linear arrangement of records

Little scope for "query optimization"