MDX Set Functions: The DRILLUPMEMBER() Function
January 3, 2006
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, please see my first article, MDX at First Glance: Introduction to MDX Essentials.
Note: To follow along with the steps we undertake within this and prospective articles of the series, the following components, samples and tools are recommended, and should be installed according to the respective documentation that accompanies MSSQL Server 2005:
The MSSQL Server 2005 and Analysis Services 2005 samples to which I refer above are available within a Microsoft Windows Installer package that accompanies the respective applications on the installation CDs, or which can be downloaded from Microsoft and perhaps elsewhere. The samples are not installed by default. If you did not install the samples and the AdventureWorks sample database during SQL Server 2005 Setup, you can install them after Setup finishes. For more information, see the topic "Running Setup to Install AdventureWorks Sample Databases and Samples" in the SQL Server Books Online. Make sure that you read and follow the installation instructions in the Readme files that accompany the samples that you want to install. For a list of samples, see the topic "Samples" in the SQL Server Books Online.
To successfully replicate the steps of the article, you also need to be a member of the appropriate group / role in Analysis Services to access the sample cube for our exercises. Read permissions are assumed for the samples upon which we will base our practice exercises, where we will often be using the AdventureWorks cube, which arrives with Analysis Services 2005 within the AdventureWorks DW Analysis Services project.
Current Service Pack updates are assumed for the operating system, MSSQL Server 2005 ("MSSQL Server"), MSSQL Server 2005 Analysis Services ("Analysis Services"), MSSQL Server 2005 Reporting Services ("Reporting Services") and the related Books Online and Samples. Images are from a Windows 2003 Server environment, but the steps performed in the articles, together with the views that result, will be quite similar within any environment that supports MSSQL Server 2005 and its component applications.
Within MSSQL Server Analysis Services 2000, we had somewhat limited options (namely, the MDX Sample Application) for easily querying our cube data sources with MDX (at least, that is, options that were available "out of the box" to anyone who had simply installed Analysis Services and its samples). MSSQL Server 2005 offers us numerous means for querying our OLAP data sources. In the interest of working within the current environment, in this and the prospective articles of the series, we will construct and execute our MDX queries, for the most part, from the SQL Server Management Studio, but we will occasionally do so from the SQL Server Business Intelligence Studio, and perhaps from other vantage points, to further enrich the learning experience within the subject matter involved. For more in-depth information on any of these various "points of approach" themselves, see the relevant sections of the Books Online, or specific articles within my various series'.
Virtually all of the MDX we constructed in earlier articles can now be used in the SQL Server Management Studio, SQL Server Business Intelligence Studio, and in various other areas within the Microsoft integrated Business Intelligence solution, and much of what we construct going forward can be executed in the MDX Sample Application (assuming connection to an appropriate Analysis Services 2000 OLAP data source). MDX as a language continues to evolve and expand: we will focus on many new features in articles to come, while still continuing to focus upon business uses of MDX in general. The use of MDX to meet the real-world needs of our business environments will continue to be my primary focus within the MDX Essentials series.
In this article, we will continue our examination, begun in Set Functions: The DRILLDOWNMEMBER() Function, of the MDX surrounding drilling up and down within our Analysis Services cubes. As we have noted, drilling up or down occurs along the lines of drilling paths that are defined within the physical structures of our cubes. "Drilling" comprises an analytical technique by which an information consumer can maneuver between summarized ("drilling up") and detailed ("drilling down") levels of data. While these drilling paths are typically specified by the cube's dimensional hierarchies, they can also 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 considered a complementary feature. We noted in Set Functions: The DRILLDOWNMEMBER() Function that the DrillDownMember() function supports the capability of Analysis Services to meet a common need for basic drilldown. Drilling up is supported by a function, DrillUpMember(), that is almost identical with respect to its operation, and which differs primarily in the "direction" (upward versus downward in the drilling path) of its action. (Several other "drill" related functions exist in MDX, which we explore in respective articles.)
Like DrillDownMember(), DrillUpMember() acts upon members within a specified set based upon members within a second specified set the difference is that the "direction" of the drill is upward in the path versus downward, as is obvious from the associated keywords. In fact, as we shall see in our practice exercise, and as we might find as a common approach to providing drilldown and drillup support within an third party application (including reporting applications like Reporting Services), DrillUpMember() can be used to deliver an uncluttered, neat drillup of a set that is produced by the DrillDownMember() function. I often use the two in conjunction in this manner to provide smooth, logical movement along drill paths.
In a manner similar to that of other functions that we have examined in the MDX Essentials series, DrillUpMember() can be useful in a host of different reporting and analysis applications. DrillUpMember(), 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.
The DrillUpMember() 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: