Provide concepts that can be understood by the user but not too far from the way data is stored in the computer. Three well-known data models of this type are relational data model, network data model and hierarchical data model.
- The Relational model represents data as relations or tables.
- The Network model represents data as record types and also represents a limited type of one to many relationship, called set type.
The Hierarchical model represents data as a hierarchical tree structures. Each hierarchy represents a number of related records. Here is the schema in hierarchical model notation.