- Hierarchical relationship: Define and give an example of it.
- Identify the UIDs in a hierarchical model
Purpose of Hierarchical Relationship
- Usually, roles are organized by hierarchy.
- Hierarchical data is very a common thing.
- Understanding how the Hierarchical model works will help you model lots of database-related things.
- A hierarchical model is a data model in which the different set if data is organized into a tree-like structure.
- The data is stored as records that are linked to each other through links.
- A record is a collection of fields, with each field having only one value.
- The type of a record sets which fields the record has.
- The hierarchical model designed to mandate that each child record has only one parent, whereas each parent record can have one or more child records.
- In order to retrieve data from a hierarchical database the whole tree needs to be traversed starting from the root node.
- We don’t need to go deeper in our explanation for this purpose, but you may want to dig more in details yourself via this source.
- Hierarchical structures are more explicit and are easier for most people to understand because they are very similar to an organizational chart.
- Each entity can have its own mandatory attributes and relationships, if the business requires this (instead of all optional attributes and relationships, as you would have in a recursive).
- In this way, your data model truly reflects the business rules.
In this article, you should have learned how to:
- Identify the UIDs in a hierarchical database model