Databases Reference
In-Depth Information
Figure 13-35
Relationships between Attributes
All the attributes within a dimension are related to the key attribute because
there is a one-to-many relationship. When you establish a relationship
between two attributes within a dimension, you can specify the type of rela-
tionship between these attributes. Two types of relationships are allowed in
Analysis Services 2005, Rigid and Flexible, and they refer to the dimension
attribute relationship changeability. Rigid relationships mean that there will be
no change in the data value for this relationship. For example, if you have the
relationship between City and State set to be rigid, it indicates that a specific
city will always belong to only one state and the initial value will never change
over time. Flexible relationships, however, mean that the values of the rela-
tionship can change over time. By default all the relationships between the at-
tributes and the key attributes of the dimension are flexible. The relationship
type determines how Analysis Services treats partition aggregation data when
you choose to perform an incremental process of the partition. Assume a re-
lationship between two attributes has been specified as rigid and the value
changes for the attribute nonetheless. When an incremental process of the di-
mension is initiated Analysis Services will present an error that the data has
changed for an attribute whose relationship has been specified as rigid.
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