Advanced Dimension Design - Professional SQL Server Analysis Services 2005 with MDX - page 331

Enhancements to Parent-Child Hierarchies

The parent-child hierarchy structure is particularly common in business so it is
very important for you to master the techniques related to it. In this section, the
concepts discussed in the previous section are extended. Several important
properties are supported by Analysis Services 2005 for parent-child hierarch-
ies. One of the important properties for a parent-child hierarchy is called the
UnaryOperatorColumn.

Unary Operators

Unary operators are used for custom rollup of members to their parent where
the rollup operation is a unary operation. A unary operator, as the name sug-
gests, is an operator that takes a single argument — the member — and rolls
up the value of the member to its parent. As with the custom rollup column,
you need to have the unary operators specified as a column in the relational
table, and this column must be set as a property for the parent-child hierarchy.
Unary operators can be applied also to non parent-child hierarchies, but that
scenario will not be covered here. The following table shows the various unary
operators supported by Analysis Services and a description of their behavior.

Unary
Operator

Description

The value of the member is added to the aggregate value of the
preceding sibling members. This is the default operator used if no
unary operator column is specified.

+

The value of the member is subtracted from the aggregate value
of the preceding sibling members.

−

The value of the member is multiplied by the aggregate value of
the preceding sibling members.

*

The value of the member is divided by the aggregate value of the
preceding sibling members.

/

~ The value of the member is ignored.