About the Series …
This article is a member of the series, MDX Essentials.
The series is designed to provide hands-on application of the fundamentals of
the Multidimensional Expressions (MDX) language, with each tutorial
progressively adding features designed to meet specific real-world needs.
For more information about the series in general, as well as
the software and systems requirements for getting the most out of the member
lessons, please see Set
Functions: The DRILLDOWNMEMBER() Function,
where important information is detailed regarding the applications, samples
and other components required to complete our practice exercises.
Overview
In this
article, we will continue the examination of "MDX for drilling up and
down" that we began in Set Functions: The DrillDownMember() Function.
We have discussed the nature of drilling, in general, in previous
articles of our sub-series, stating that it comprises an analytical technique
through which means an information consumer can maneuver between summarized ("drilling
up") and detailed ("drilling down") levels of data. We
noted that drilling up or down occurs along the lines of drilling paths
that are defined within the structure of our cubes, and which are typically
specified by the cube’s dimensional hierarchies. We mentioned, too, that these
paths can be based upon alternative relationships that exist within or between
dimensions.
An example might be described as follows, based upon an engagement
within which I have recently been involved: An executive within a state Department
of Education wishes to examine annual Adequate Yearly Progress (AYP)
data within a cube constructed primarily to allow comparison and analysis of
those results at various levels. The executive can examine national averages,
numbers of test takers, and various other measures, and then perform a
drilldown operation within a Geography dimension that might then present
the data by states. He could then perform subsequent drilldowns to
display state regions (or perhaps even congressional districts), counties
/ school systems, and more. Depending upon the design of the cube, the drilldown
process could ultimately take the consumer to the level of the individual schools
– perhaps even to the individual students themselves.
Drilling up is a capability that might be taken for
granted in a drilldown scenario such as the foregoing. From any of the drilled
down levels at which the information consumer finds himself or herself, a
corresponding capability to navigate upward, from more detailed
levels of data to more summarized levels of data, would be an
expected complementary feature.
In an earlier article, Set
Functions: The DrillDownLevel() Function, we introduced the "primary,"
level-directed MDX drilldown function, DrillDownLevel(), stating that it
supports the capability of Analysis Services to meet the common need for
drilldown from a point within a given Set to members within the next
lower level, or to a level which we can specify using an optional Level
Expression (or, alternatively, an optional Index). Drilling up from
a level-directed perspective is supported by a function, DrillUpLevel(),
that is quite similar to DrillDownLevel(), with respect to its
operation, differing, of course, in the "direction" (upward
versus downward, along the drilling path) of its action.
In this article we will
examine a means for drilling in the "upward" direction, through the DrillUpLevel()
function, another "staple" support function underpinning drill
capabilities within MDX. DrillUpLevel() drills up the members of a set
to a higher level. It drills up each member of a specified set that
exists below a level that we can optionally specify. (If we do
not specify the level, the function identifies the lowest level in the
set, and removes the members that reside at that level, to present a drilled up
state at the next level).
In a
manner similar to other functions that we have examined in the MDX
Essentials series, DrillUpLevel() can be useful in a host of
different reporting and analysis applications. DrillUpLevel(), along with other "navigational"
functions like it (virtually all of which we examine in other articles of this
series) allows us to exercise a great deal
of presentation sleight of hand, in working with MDX in Analysis Services,
as well as within Reporting Services and various other reporting
applications that can access an Analysis Services cube. Like other MDX functions in general, the DrillUpLevel() function can be leveraged, within
and among the various "layers" of the Microsoft integrated
Business Intelligence solution, to support sophisticated presentations and
features. We will introduce the function, commenting upon its operation and
touching upon examples of effects that we can employ it to deliver. As a part
of our discussion, we will:
- Examine the syntax surrounding the function;
-
Undertake illustrative examples of the uses of the function in
practice exercises; -
Briefly discuss the results datasets we obtain in the practice
examples.
