C.1: Hierarchical Data in a RDB
We know that it is difficult to store hierarchical data in a RDB. The basic knowledge in order to know the difficulties, are summarized in the following link. Please read at first, because it contains important information in order to understand the fifth model.
C.2: Conventional Models
DB engineers around the world had been studying the four models for clearing the problem. These are "adjacency list model," "path enumeration model," "nested set model", "closure table model".
When you want to know about the conventional model, please refer to the following link. If you had already understood deeply them, can skip to read it.
C.3: The Fifth Model
"Fertile forest model" is designed to store hierarchical data in RDB with the new approach which is different from conventional models. Big features are three points as:
- A number of columns to store hierarchical data in RDB, is so few.
- Can describe variety queries to find flexibly.
- All basic query to find with index.
FF model will be a solution for storing hierarchical data in a RDB. Please learn more from the following link.