Parent-Child Dimensions

A parent-child dimension table is one in which the hierarchical relationships are defined by a parent column and a child column. Since the hierarchy is defined by the relationship between the values within two columns, a parent-child dimension is sometimes referred to as having a value-based hierarchy.

Figure 25-1, "Sample Parent-Child Dimension Table Columns" illustrates the relationships between the values in the child and parent columns. A description column, which is an attribute of the child, is also included.

Figure 25-1 Sample Parent-Child Dimension Table Columns

CHILD           PARENT         DESCRIPTION 
-------------   -----------    -------------
World                          World
USA             World          United States of America
Northeast       USA            North East Region 
Southeast       USA            South East Region 
MA              Northeast      Massachusetts
Boston          MA             Boston, MA 
Burlington      MA             Burlington, MA 
NY              Northeast      New York State
New York City   NY             New York, NY
GA              Southeast      Georgia
Atlanta         GA             Atlanta,GA
Canada          World          Canada

If you choose to create OLAP Catalog metadata to represent a parent-child dimension, set the solved_code for the hierarchy to SOLVED,VALUE_BASED, as described in Chapter 20, "CWM2_OLAP_HIERARCHY".