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The Aggregate Function

Reporting Services supports an Aggregate function to retrieve aggregated values directly from the data provider if the provider supports this feature. The Aggregate function is especially useful with retrieving data from Analysis Services because it may be difficult if not impossible to recreate aggregated values on the report, such as when the cube script overwrites the server aggregates.

It’s easy to use the Aggregate function. Just replace the default Sum() aggregate function with Aggregate() in the group subtotals. When you do this, the Analysis Services provider brings in additional rows that include the server aggregates which the report displays in the group subtotals.

Recently, I came across a report that would return the following exception after attempting to use Aggregate().

The Value expression for the text box ”<textbox.’ uses Aggregate with an invalid scope parameter.

I couldn’t find anything wrong with the way Aggregate() is used because it was in the right place on a crosstab report. Robert Bruckner from the Reporting Services team helped me understand the Aggregate() function limitations:

The Aggregate function can only be used if the current scope and all parent group scopes are all based on simple field references (e.g. =Fields!Accounts.Value), or constants. The Aggregate function also cannot be used in detail rows.

In my case, the report was using a parent-child Analysis Services hierarchy. To show the data recursively, the tablix Details group was set to group on =Fields!Account.UniqueName. This is an extended property that the SSAS provider supports and it’s not a simple reference. Changing the grouping to =Fields!Account.Value resolved the issue.

Phantom URLs

An interesting “issue” popped up today. I did a fresh install of Windows 7 on my brand new HP 8530w laptop, which is a great laptop BTW. I install SQL Server 2008 followed by SP1 only to find that the Web Service URL and Report Manager URL don’t show up in the Reporting Services Configuration Manager.

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The report sever would run just fine on http://localhost/reportserver and the URLs were registered correctly in the rsreportserver.config. I went as far as whipping out some WMI code and it would return the URLs as it should. But the darn URLs won’t show up. Not to mention that another user has recently reported the exact same issue to me. A bug? I started thinking of re-installing SQL Server.

Then, a Eureka moment! As with most things, there was an easy explanation. For some reason, Windows 7 has set the system font size to be 125%. Resetting it to 100% fixed the issue although it could have been a good idea to increase the label height in Reporting Services Configuration Manager to avoid such font scaling issues.

Passing Multivalued Parameters in SQL Server 2008

One year after submitting this small article, SQL Server Magazine has finally published it. This article demonstrates how you can use table-value parameters (TVPs), a new feature in SQL Server 2008, to let you pass multivalued parameters from a report to a stored procedure.

The code can be downloaded from the SQL Server Magazine site or from here.

Heat Maps as Reports

Continuing my intrepid journey through the new Reporting Services R2 enhancements, in this blog I’ll demonstrate some of the cool map features. As you’ve probably heard, R2 brings a brand new map control that lets you visualize spatial data on your reports. Since mapping is the one of the major enhancements in R2, there will be plenty of resources to cover it in details. For example, Robert Bruckner has written a great blog to get you started with mapping. The SSRS R2 forum adds more resources.

But what if you don’t need to visualize geospatial data, such as restaurants in the Seattle area? You shouldn’t bother with the map, right? Not so fast. What’s interesting is that the map supports the two spatial data types in SQL Server: geography and geometry. The latter lets you visualize everything that can be plotted on the planar coordinate system. That’s pretty powerful when you get to think about it. If you have the item coordinates, you can map pretty much everything. A few weeks ago, for example, I saw a Microsoft sample map report that plotted floor layout. Today, I’ll show you a report that I whipped out during the weekend that demonstrates how to visualize a heat map.

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The Heat Map Report

A heat map is a graphical representation of data where the values taken by a variable in a two-dimensional map are represented as colors. The most basic variation of a heat map is a tree map that lets you visualize data trends presented as nested rectangles. In our case, the sample report shows the Adventure Works reseller sales. As shown in the screenshot, the larger the rectangle is the more sales were contributed by that reseller. The same can be observed by analyzing the rectangle color which ranges from green (most sales) to red (less sales). The greener the color is, the more sales that reseller has. I chose to use the sales as a color variable although I could have used another measure, such as number of employees, profit, etc. You can download the source code from here.

Limitations

I’ll be quick to point out the following limitations of this reporting solution:

  1. As it stands, producing the report requires a two-step approach. First, you need to prepare the dataset and save it in a SQL Server table. Second, you run the report from the saved data. Unfortunately, the ReportViewer control doesn’t support RDL R2 which means it doesn’t support maps, so you cannot bind the dataset and run the report in one shot. While we are waiting for Microsoft to update ReportViewer, you can use a server-side custom data extension that exposes the ADO.NET dataset with the spatial data as a report dataset. This approach will et you bind the ADO.NET dataset to a server report. Chapter 18 in my book source code includes such an extension.
  2. The performance of the algorithm that I use to calculate the coordinates of the nested rectangles degrades after a few hundred rows in the dataset. If you need to map more results, you may need to revisit the algorithm to see if you can optimize it.

Understanding Rectangle Geometry

SQL Server describes polygons in Well-Known Text (WKT) standard sponsored by Open Geospatial Consortium. For instance, a polygon is described as five (surprise) points on the coordinate system, as shown below. The fifth point is the same as the first point.

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You can convert WKT to the SQL Server geometry data type by using the STPolyFromText method, such as:

geometry::STPolyFromText(‘POLYGON ((0 0, 0 125.6331, 115.0095 125.6331, 115.0095 0, 0 0))’, 0)

Calculating the Coordinates

To calculate the nested rectangle coordinates, I used the excellent Squarified Treemaps algorithm by Jonathan Hodgson. Jonathan explains in details how the algorithm works. My humble contribution added the following changes:

  1. I decoupled the algorithm from his Silverlight solution to a C# console application.
  2. Instead of loading the sample dataset from a XML file, I load it from the Analysis Services Adventure Works cube. Specifically, the MDX query returns the top fifty resellers order by Reseller Sales.
  3. I added Console.WriteLine statements to output insert queries which you can execute to populate the Test table.

CREATE TABLE [dbo].[Test](

    [ID] [int] IDENTITY(1,1) NOT NULL,

    [Name] [varchar](50) NULL,

    [Shape] [geometry] NOT NULL,

    [Size] [decimal](18, 5) NULL,

    [Area] AS ([Shape].[STArea]()),

CONSTRAINT [PK_Test] PRIMARY KEY CLUSTERED

(

    [ID] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]

GO

insert into test(Shape, Size, Name) values (geometry::STPolyFromText(‘POLYGON ((0 0, 0 125.6331, 115.0095 125.6331, 115.0095 0, 0 0))’, 0), 877107.2, ‘Brakes and Gears’)

insert into test(Shape, Size, Name) values (geometry::STPolyFromText(‘POLYGON ((0 125.6331, 0 247.9348, 115.0095 247.9348, 115.0095 125.6331, 0 125.6331))’, 0), 853849.2, ‘Excellent Riding Supplies’)

Once you execute the INSERT statements to populate the Test table, you can use the SQL Server spatial data visualizer to view the results:

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Authoring the Report

Once you have the data, authoring the report is easy.

  1. Create a new report in Report Builder 3.0 Add a dataset that uses the following query:
    SELECT * FROM Test
  2. Click the Map icon to start the Map wizard.
  3. On the Choose a Source for Spatial Data step, choose the SQL Server Spatial Query option and click Next.
  4. On the Choose the Dataset step, select the Dataset from step 1.
  5. On the Choose Spatial Type, the map wizard should identify the Shape column as a geometry data type. At this point, the pre-release Report Builder 3.0 shows an empty map because it doesn’t recognize the coordinate system as Planar. Don’t worry, we’ll fix this later.
  6. On the Choose Map Visualization, select the Color Analytical Map option.
  7. On the Choose the Analytical Dataset step, select the same dataset because it has a Size column (reseller sales) that we will use for the color visualization.
  8. On the Choose Color Theme step, choose =Sum(Fields!Size.Value) for a field to visualize and Red-Green as a color rule because the resellers with less sales will be coded red. Click Finish to exit the wizard.
  9. In design mode, select the map and change the Viewport CoordinateSystem property to Planar.

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Once you’ve changed the coordinate system, the polygons should magically appear. I’ve made a few more changes but you should be able to understand them by examining the map properties.

During my Reporting Services Tips and Tricks TechEd 2009 presentation, one of my most important tips was to encourage you to write more reports and less custom code. I showed a cool SharePointb-ased dashboard that we built by assembling report views. Following this line of thought, consider report maps instead of writing custom code when you need to visualize spatial data of any kind.

Reporting Services 2008 Online Training Class with Teo Lachev

There is still time to sign up for our Applied Reporting Services 2008 class with Teo Lachev. This three-day intensive event teaches you the knowledge and skills you need to master Reporting Services to its fullest. No travel, no hotel expenses, just 100% in-depth SSRS training delivered right to your desktop!

072809_2347_AppliedRepo1Applied Reporting Services 2008 Online Training Class
with Teo Lachev
Date: August 31 – September 2, 2009
Time: Noon – 4 pm EDT; 9 am – 1 pm PDT
12 training hours total for only $799!
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Attend this class for only $799 and get a free paper copy of the book Applied Microsoft SQL Server 2008 Reporting Services by Teo Lachev!

For more information or to register click here!

SQL Server 2008 R2 August Community Technology Preview Available

Microsoft released SQL Server 2008 R2 August Community Technology Preview which includes the Report Builder 3.0 R2 August CTP redistributable.

Reports as Data Feeds

Reporting Services SQL Server 2008 R2 features reports as Atom data feeds. This is accomplished with a new Atom Data Feed extension, as shown on this screenshot.

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This extension produces an atom service document (an *.atomsvc file). It lists at least one data feed for each data region in a report. In fact, some regions, such as tablix with column groups (cross-tab report layout) may generate multiple feeds.

At this point, you probably imagine subscribing to reports and receiving feeds in Outlook when report data is changed. Unfortunately, you won’t get very far doing so. As it turns out, atom data feeds are different from Atom feeds that most applications, such as IE and Outlooks understand directly. So even if you extract the Url out of the service document and display the .atom rendering of a report in IE, the browser won’t show useful information because it doesn’t understand that the data rows in the data feed are the important part.

So, how are report data feeds useful then? At this point, the design goal for reports as data feeds was to support Gemini – the new Excel 2010 extension that lets end users build in-memory cubes. Gemini can acquire data from variety of data sources, including data feeds and SSRS reports. Here is what it takes to subscribe to a report feed.

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  1. In the Gemini add-in, click the From Data Feed button.
  2. On the Connect to Data Feed step of the Table Import Wizard, browse to the data feed file you exported from the report. In this case, I am pointing to the atomsvc file exported from Company Sales 2008 report. On this step, you can set up advanced options, such as timeout, authentication, etc, and test the feed.

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  3. On the Select Tables and Views step, select the regions on the report whose feeds you want to subscribe to. Since Company Sales 2008 has only one region, only one data feed is exposed. You can click the Preview button to preview the feed data. In the preview window, you can select which columns to import and set up a row filter (doesn’t seem to be working in the August CTP).

    081409_0200_ReportsasDa4Reporting Services, Analysis Services, Microsoft Office, SQL Server 2008 R2

  4. On the Import Summary step, preview the feed options and click Finish to import the data.

This imports the feed data into the Excel spreadsheet. From there, you can use Gemini to build the in-memory model and analyze the report data.

Reporting Services Lookup Functions

One new SSRS SQL Server 2008 R2 feature that caught my attention is lookup functions. When reading the Reporting Services discussion list, I come frequently across questions that ask if it is possible to look up a value from a dataset other than the dataset the region is bound to. Excluding getting the first or last value (First and Last functions) or aggregate functions that work on the entire dataset, the only solution was to cache the dataset in a report code-behind code and use custom code to perform the navigation.

R2 will change this by introducing Lookup, LookupSet, and Multilookup functions. The lookup functions are best understood with an example. Take a look at this report (attached) which is based on the Sales Order Detail 2008 report that ships with the Adventure Works sample reports.

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I added a couple of textboxes to the report. The order details section includes a Sales Person field that displays the sales person’s name. What’s interesting is that the sales person name is retrieved from the SalesOrder dataset that feeds the order header section. Just to address the question that I can almost hear you asking, no, R2 will not support joining datasets at a report level. Instead, I use the Lookup function which performs on-the-fly search, as follows:

=Lookup(Fields!SalesOrderID.Value, Fields!SalesOrderID.Value, Fields!SalesPerson.Value, “SalesOrder”)

I pass the field of the SalesOrderDetail dataset (Fields!SalesOrderID.Value) on which the lookup will be based. I pass the field of the SalesOrder dataset that will be matched. As a third argument, I pass the field (Fields!SalesPerson.Value) of the SalesOrder dataset that I need. Finally, I pass the name of the dataset (“SalesOrder”) that will be searched. The Lookup function is executed for each row in the source dataset.

In the order header section, I display the third item total from the SalesOrderDetails dataset by using the LookupSet function, as follows:

=Code.GetValueByRowNumber(LookupSet(Fields!SalesOrderID.Value, Fields!SalesOrderID.Value, Fields!LineTotal.Value, “SalesOrderDetail”), 2)

You call LookupSet in the same way you call Lookup. The difference is that Lookupset returns a variant array of all values that match. I decided to make the demo more interesting and let you specify the row index needed by adding a simple function to the report code.

Function GetValueByRowNumber(ByVal items As Object(), ByVal pos as Integer) As Object

If items Is Nothing Then

Return Nothing

End if

 

If pos > items.Length -1 Or pos<0

Return Nothing

End If

 

Return items(pos)

End Function

 

The expression passes the variant array returned by LookupSet and the row index to the GetValueByRowNumber. The GetValueByRowNumber returns the field at that row.

The Multilookup function, which I don’t demonstrate, accepts an array of source values to match and returns an array of the matched values that have 1:1 relationship to the source values, such as:

=MultiLookup(Split(Fields!CategoryList.Value,”,”) , Fields!CategoryID.Value, Fields!CategoryName.Value,”Category”))

[View:/CS/cfs-file.ashx/__key/CommunityServer.Blogs.Components.WeblogFiles/blog/7532.Sales Order Detail 2008.rdl]

The Dazzling R2 Report Manager

In this and future blogs I’ll cover the most important new features in the forthcoming release of Reporting Services which will be included in SQL Server 2008 R2 (code-named Kilimanjaro or KJ for short). Let’s start with the most obvious new feature: the all new Report Manager UI.

SharePoint-like UI

The moment you open Report Manager, you will notice that significant work was done to make the UI more intuitive, a la SharePoint.

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For example, similar to SharePoint, a drop-down context menu pops up when you hover on a report item that lets you quickly access relevant tasks.

Simplified UI

The management pages also received facelift. Microsoft has reduced the number of buttons and changed the tab styling so you are sure which tab is selected.

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Although seemingly minor, I am sure you’d love the new look and feel. For example, I like the fact that I don’t have run a report or switch to Details mode just to get to the report properties.

Report Builder 3.0 ClickOnce

Another welcome enhancement is that opening a report in Report Builder, launches Report Builder 3.0 (more on it in another post) by default. Report Builder 1.0 is still installed but it’s not the default reporting client. You see the writing on the wall. Report Builder 1.0 days are counted and you better embrace the future.

AJAX Report Viewer

Another major enhancement is the debut of an AJAX-enabled ReportViewer control (developers will get the Visual Studio counterpart in Beta 2 of Visual Studio 2010). The control eliminates visible page reposts when interactive actions, such as drilldown, are initiated. The page fades out but it stays in place and a spinny lets the user know that an interactive action is taking place.

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All in all, end users and administrators will enjoy the new Report Manager. You won’t have to switch to SharePoint integration mode just to get a SharePoint-like UI.

New Reporting Services Features in SQL Server 2008 R2 CTP2

It turned out that for time being the CTP2 of SQL Server 2008 R2 which I announced yesterday is available for TAP participants only. It will be publicly available on Wednesday. Meanwhile, Robert Bruckner listed the new Reporting Services features which got implemented in CTP2. The biggy is the new map region that lets you visualize geospatial and geometry data.

In my first book I had a sample that demonstrated how to export a report as a data feed. Well, in R2 this will be natively supported. Reports as data feeds, anyone? Visual Studio 2010 Beta 2 will include an AJAX Report Viewer. I would hope for a Silverlight version but one step at a time.

Again, post your KJ-related question to the Reporting Services forum.