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Posted May 22, 2008

Intrinsic Member Properties: The MEMBER_CAPTION Property - Page 2

By William Pearson

Procedure: Use the MEMBER_CAPTION property in another example to Provide Parameter Picklist Support in Reporting Services

Let’s look at an example that expands upon our first, this time to meet a mechanical need within the reporting layer of an integrated BI application. As many of us are aware, enterprise reporting applications typically allow for parameterization (via what are sometimes known as “prompts” or “parameter prompts”) to enable information consumers to quickly find the information they need from a report. These parameters, whose values are physically passed to an axis specification or a slicer in the dataset query, often act to put filters into place “on the fly;” the “filters” are thus enacted when the consumer types or selects a value, or a series of values, at run time.

In general, there are two primary types of parameters, type-in and picklist, which can be mechanized through various means. Type-in parameters accept directly typed user input for the value upon which the report is based. An example of input might, for a report based upon an Analysis Services cube, consist of the Unique Name for a given filter, say, for one of the Customer Geography Cities in the list we created earlier.

The trouble with type-in parameters is that they are subject to input error, and thus can fail to produce the desired results if they are not precisely correct. This can be particularly cumbersome for information consumers when the report is based upon an Analysis Services cube, because, even with a list like the one we generated above with the Unique Names mapped to the “English” names for various filter selections, the precise MDX qualified name might present a typing challenge for some.

For this reason, the alternative parameter type, the picklist, provides a more user-friendly experience. A picklist presents a selection of choices to a consumer, based upon a static file, a dataset from a larger data source, or through other means. The picklist is often the tool of choice, because of its inherent elimination of typing errors. A well-constructed picklist makes selection easy for the consumer (who is not often pleased with a long scrolling process, or other cumbersome method, as the initial step in generating a commonly requested report). An investment in developing a good picklist often pays great dividends in consumer satisfaction.

The list we have generated above provides virtually all we need to support parameterization within Reporting Services and other enterprise reporting applications. Let’s do another example, this time with picklist support the primary objective. We will construct a dataset upon which the picklist selections can be based, and then examine briefly an illustration of the use of this dataset in MSSQL Server Reporting Services.

Let’s assume, as a background scenario, that, in contacting us to say that they are happy with the index we have provided for the developer as outlined in our previous example, the Reporting department with which we worked earlier asks for further assistance of a similar nature. Their next request is a common one: they want to provide picklist support within an OLAP report, which they have constructed using MSSQL Server Reporting Services. The data source is, once again, the Adventure Works sample cube that accompanies an installation of MSSQL Server Analysis Services 2005 (and with which most of us are familiar). The consumers want the selector for the parameter picklist to display the regular Name for the Product Categories each time an information consumer runs the report.

While the focus of our article is the MDX required to meet this request, and specifically upon the use of the MEMBER_CAPTION property within an MDX query, the dataset that this query generates would be added in Reporting Services’ Report Designer, among other steps, to meet the requirement for parameterization within the designated OLAP report. Let’s create a query to generate the list, and then take a look at how we might use the data returned within the reporting layer.

Our initial approach is quite similar to the previous example – it’s in the intended end use of the returned data where we do something different. We again have a need that we can readily answer using the MEMBER_CAPTION property in conjunction with a relative function, .CurrentMember. The solution also includes the .UniqueName function. We will be targeting the Caption column in the resulting dataset (we’ll call it Product Category - Caption) for the name that is displayed in the selector for the parameter picklist. The Unique Name column of the returned dataset (the qualified “MDX” name for each Category member of the Product dimension, Product Categories attribute hierarchy), which we call Product Category – MDX Qual Name in the query we construct, will serve as the value that is actually passed to the cube in the MDX of the query. The happy result is that we insulate report consumers from the MDX altogether, while providing them ad hoc selection of a Product Category upon which to filter the report data.

Our first step is to construct a query to return the requested Product Category list, presenting the selector Captions and Unique Names in two side-by-side columns. The corresponding Product Category members of the Product dimension (Product Categories attribute hierarchy) will inhabit the row axis, as we shall see.

1.  Select File --> New from the main menu, once again.

2.  Select Query with Current Connection from the cascading menu that appears next, as depicted in Illustration 3.

Illustration 3: Create a New Query with the Current Connection ...

A new tab, with a connection to the Adventure Works cube (we can see it listed in the selector of the Metadata pane, as expected) appears in the Query pane.

3.  Type (or cut and paste) the following query into the Query pane:

-- MDX066-02  Using .Member_Caption and .UniqueName to 
--   generate a picklist selection
   [Measures].[Product Category - Caption]
   '[Product].[Product Categories].CurrentMember.MEMBER_CAPTION'
   [Measures].[Product Category - MDX Qual Name]
   '[Product].[Product Categories].CurrentMember.UNIQUENAME '
   {[Measures].[Product Category - Caption], 
      [Measures].[Product Category - MDX Qual Name]} 
         ON AXIS(0),
   {[Product].[Product Categories].[Category].MEMBERS}
     ON AXIS(1)
   [Adventure Works]  

The Query pane appears, with our input, as shown in Illustration 4.

Illustration 4: Our Second Query in the Query Pane ...

4.  Execute the query by clicking the Execute (!) button in the toolbar.

The Results pane is populated by Analysis Services, and the dataset depicted in Illustration 5 appears.

Illustration 5: Results Dataset – Another Use of MEMBER_CAPTION and .UniqueName with .CurrentMember

We see Captions for the individual Product Categories, the output of the Product Category - Caption calculated member, populating the first data column. The respective Product Category Unique Names (again, the “qualified” MDX name that can be used within a query against the Adventure Works cube) - the output of the Product Category – MDX Qual Name calculated member - occupy the second data column. The Product Category attribute hierarchy members themselves occupy the row axis, as our client colleagues have requested (the row axis will not be used in the reporting environment). The calculated members Product Category - Caption and Product Category - MDX Qual Name employ the MEMBER_CAPTION property and .UniqueName function, respectively, in conjunction (again) with the “relative” .CurrentMember function, which, as we can easily see from our practical example, results in a combination list of the Captions / Qualified Names of the members that we specify in our row axis.

5.  Select File > Save As, name the file MDX066-02, and place it in a meaningful location.

We will not take the steps, within this article, which occur inside the reporting layer to construct the picklist apparatus. However, let’s take a look at one approach to assembling the parts in Reporting Services (or, similarly, in another OLAP reporting application). First, we would transfer the query to Reporting Services’ own Data tab to generate a dataset within the report under consideration. This query, together with the dataset it generates, would look something similar to that which is partially shown in Illustration 6.

Illustration 6: Constructing a Dataset in Reporting Services to Support a Parameter Picklist

NOTE: This is only one approach to creating the dataset – perhaps the more obvious of several. Another might be more optimal, depending upon the reporting environment under consideration. Other approaches, the components of which might occupy different layers of the Microsoft integrated business intelligence solution, might include installation of the calculated members at the cube level, and then calling (versus defining and building) them from the reporting layer.

For a step-by-step procedure that demonstrates the construction of such a cube-based solution to support a picklist in Reporting Services, see Create a Cube-Based Hierarchical Picklist in my MDX in Analysis Services series, or Parameterization from Analysis Services – Cascading Picklists in my MSSQL Server Reporting Services series here at Database Journal.

Once we have created the dataset, the next step is to add a parameter to the report. Inside the Report Parameter definition, we would reference the new dataset (in the example I created for my illustrations I named it ProductCategory), as shown, and then select Product Category - MDX Qual Name and Product Category - Caption the Value and Label fields respectively. Illustration 7 presents a view of the way all this would tie together in the Report Parameter dialog inside Reporting Services.

Illustration 7: Pulling It All Together inside the Report Parameter ...

At this point all that remains is to return to the primary dataset underneath the report and to insert the parameter variable within an axis specification or a slicer, where it acts as a filter (there are examples of this, and all other steps, in the articles I have cited above). Executing the query then triggers the “prompting” action of the new Product Category parameter.

The selection list, displaying the regular Product Category name, is manifested in the parameter dropdown when we preview or execute the report, as partially depicted in Illustration 8.

Illustration 8: The Product Category Parameter Selector in Action ...

And so we see that our query, using the MEMBER_CAPTION property and .UniqueName function, in conjunction with the “relative” .CurrentMember function, to present the Captions and Unique Names for the Product Categories in two side-by-side columns, can be readily used to support a picklist for a parameter within the reporting layer of the business intelligence solution of our client. Having demonstrated the workings of the MEMBER_CAPTION property and .UniqueName function in this fashion has helped us to show our client colleagues that we have, within the current dataset query, established support for parameterization based upon underlying cube data.

Our client colleagues express satisfaction with the results, and confirm their understanding of the operation of the MEMBER_CAPTION property within the contexts we have presented in the practice exercises. We reiterate to the Reporting team that knowing “where to put the intelligence” within the various layers of the Microsoft integrated BI solution can mean highly tuned performance and effective solutions for consumers throughout our organizations.

6.  Select File -> Exit to leave the SQL Server Management Studio, when ready.

Summary ...

In this article, we introduced the MDX MEMBER_CAPTION property, which can be called upon in activities that range from generating simple lists to supporting parameters in the reporting layer, as well as more sophisticated uses. We introduced the function, commenting upon its operation and touching upon the datasets we can deliver using MEMBER_CAPTION.

We examined the syntax involved with MEMBER_CAPTION, and then undertook a couple of illustrative practice examples of business uses for the function, generating queries that capitalized on its primary features. Our exercises included an example that drew upon our earlier examination of the .UniqueName function, which we used in combination with MEMBER_CAPTION to create a results dataset. We then illustrated using a similar dataset to support a parameter picklist in a report that queried an Analysis Services data source. Throughout our practice session, we briefly discussed the results datasets we obtained from each of the queries we constructed.

» See All Articles by Columnist William E. Pearson, III

Discuss this article in the MSSQL Server 2000 Analysis Services and MDX Topics Forum.

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