Architecture of Query Execution—Calculating MDX Expressions - Microsoft SQL Server 2008 Analysis Services - page 530

Scope Object

Calculated Members

Calculated Cells

Named Sets

Actions

KPIs

Visual Totals

Default Members

FIGURE 29.5

The Scope object contains all the calculations that Analysis Services supports.

. Subcube scope contains a restriction subcube defined by the SubSelect clause or the

CREATE SUBCUBE statement.

All these types of scope derive from each other and make up a stack, with global scope on
the bottom and, in the most general case, subcube scope on top. The type of the Scope
object on the top of the scope stack depends on the MDX statement being executed. If the
current statement is a SELECT statement with subselect , the subcube scope is on the top.
If it's a regular SELECT statement, the query scope is on top of the stack. If the query is a
CREATE statement, session scope is on top of the stack. Figure 29.6 shows the stack of
scopes. Each scope has a reference to its parent —the scope immediately below the current
one in the stack.

When Analysis Services performs lookups for calculations that might reside in any of the
scopes, it starts to iterate from the top of the stack, following parent references. This
makes calculations defined in any scope available during the query execution.