Hierarchies are an important part of all business intelligence solutions, used to describe dimensions that naturally contain different levels of granularity.
A hierarchy always consists of a number of members – nodes – that have one parent each. In the general case, each node can have any number of children.
There are several approaches for storing hierarchies in a relational model.
One way is - Adjacent List Model (Adjacent Nodes Table).
The principle is that each node is stored in its own record, and that each record has a foreign key pointing out the parent. In other words; there is exactly one record per node.
This is going to be the input for HIERARCHY-LOAD statements. The output will be in Expanded Nodes Table.
Input Table Format: Adjacent Nodes Table
Output Table Format: Expanded Nodes Table
Note that the resulting Expanded Nodes table has exactly the same number of records as its source table (one per node); but with number of additional Columns.
Note: Please check the documents mentioned in the Reference Column for detailed explanation. This document focuses only on various combinations of Arguments used in the HIERARCHY statement.
I have tried to use different Arguments in the 'Hierarchy LOAD' Statement and captured it's result with a very basic data-set.
I hope this will be helpful for Beginners.