👑 Hierarchical Data Model
Also known as HDM
Pros#
- Data can be retrieved easily due to the explicit links between the table structure
- Referential integrity is always maintained. i.e. any changes made in the parent table are automatically updated in a child table
- Promotes data sharing
- It is conceptually simple due to the parent-child relationship
- Database security is enforced
- Quick access at root nodes
- Efficient with 1:N relationships
- A clear chain of command or authority
- Increases specialisation
- Clean results
- High performance
Cons#
- If the parent table and child table are unrelated, then adding a new entry in the child table is difficult because affitional entries muct be added in the parent table
- Complex relationships are not supported
- Redundancy which results in inaccurate information
- M:N relationships are not supported
- No data manipulation or data definition language
- Lack or standards
- Poor flexibility
- Difficult to implement into a database
- Organisational disunity
- Rigid structure
What does the N mean?#
N mean many
Example:
M:N = Many to Many
Disunity#
NOUN
1. Disagreement and conflict within a group