3.10 Data Models

The hierarchical data model organises data in a tree‑like structure, where each parent can have multiple children, but each child has only one parent.

Purpose: Simple, structured relationships.

Example diagram: Hierarchical data model diagram

The network data model allows records to have multiple parent and child relationships, forming a graph structure.

Purpose: More complex relationships than hierarchical models.

Example diagram: Network data model example

The relational data model stores data in tables made up of rows and columns, with relationships defined using keys.

Purpose: Flexible, efficient data storage and retrieval.

Example: Relational data model tables

The choice of data model is influenced by:

• Efficiency of accessing individual data items
• Efficiency of data storage
• Level of complexity in implementation and maintenance

Hierarchical: Simple and fast but inflexible.
Network: Flexible but complex to design and maintain.
Relational: Highly flexible and efficient but may require more processing for complex queries.

Organisations must balance efficiency and complexity when selecting a data model for digital support and security.

Data models can be represented as:

• Hierarchical models – blocks, arrows, and labels
• Network models – blocks with multiple connecting arrows
• Relational models – tables with rows, columns, and keys

Visual examples:

• Data model diagrams overview
• Illustrated data model representations