Value-based Hierarchies

A value-based hierarchy is a dimension in which hierarchical relationships are defined by a parent dimension attribute and a child dimension attribute. This is different from a level-based hierarchy, referred to as a hierarchy in this chapter, in which the hierarchical relationships are defined between levels.

You create a value-based hierarchy when the parent-child relationships cannot be grouped into meaningful levels. A value-based hierarchy has no levels. When you create the dimension attributes, you must specify which dimension attribute is the parent attribute.

For example, consider an EMPLOYEE dimension that has the following dimension attributes: ID, FIRST_NAME, LAST_NAME, EMAIL, PHONE, JOB_ID, HIRE_DATE, DESCRIPTION, and MANAGER_ID. This dimension contains a parent-child relationship in which the MANAGER_ID attribute identifies the manager of each employee. But these relationships may not form meaningful levels across the organization. This is because the number of levels between an employee and the CEO is not the same for all employees. There may be four levels between employee A and the CEO, whereas, there may be six levels between employee B and the CEO. In such cases, you create a value-based hierarchy with MANAGER_ID as the parent identifier.

You can create value-based hierarchies using the Data Object Editor only. For more information about specifying a parent attribute, see "Attributes Tab" in Warehouse Builder Online Help.