Tài liệu Sams Microsoft SQL Server 2008- P10 doc

ptg 431 Code Examples 24 Dim message As String Console.WriteLine(“Current Jobs”) Console.WriteLine((“================================” + Environment.NewLine)) Dim job As Job For Each job In jobs If job.Status = JobStatusEnum.Running Or job.Status = JobStatusEnum.[New] Then ‘ New goes away soon Console.WriteLine(“————————————————”) Console.WriteLine(“JobID: {0}”, job.JobID) Console.WriteLine(“————————————————”) Console.WriteLine(“Action: {0}”, job.Action) Console.WriteLine(“Description: {0}”, job.Description) Console.WriteLine(“Machine: {0}”, job.Machine) Console.WriteLine(“Name: {0}”, job.Name) Console.WriteLine(“Path: {0}”, job.Path) Console.WriteLine(“StartDateTime: {0}”, job.StartDateTime) Console.WriteLine(“Status: {0}”, job.Status) Console.WriteLine(“Type: {0}”, job.Type) Console.WriteLine(“User: {0}” + Environment.NewLine, job.User) runningJobCount += 1 End If Next job If runningJobCount = 1 Then message = “There is 1 running job. “ Else message = String.Format(“There are {0} running jobs. “, runningJobCount) End If Console.Write(message) If runningJobCount > 0 Then Return True Else Return False End If End Function The example’s output is shown here: Current Jobs ================================ ———————————————— JobID: jgbfw045virghsnsgvbv4n55 ———————————————— Action: Render Description: Machine: SSRS2 From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 432 CHAPTER 24 RS Utility Name: Company Sales Path: /AdventureWorks Sample Reports/Company Sales StartDateTime: 9/29/2008 8:39:17 PM Status: New Type: User User: SSRS2\Administrator There is 1 running job. The command completed successfully Some other useful scripts that you can execute with the RS utility include the following: . Deploy new reports (RDL files) and data sources . Configure data sources . Download contents of the Report Server . Deploy to multiple servers simultaneously . Set up subscriptions . Refresh caches As you can see, the RS utility can be used to accomplish almost anything you could use the Reporting Services web service to do. The work would be in developing script files to do it. Summary This chapter serves as an introduction to the RS utility. The RS utility can be used in conjunction with the web service endpoints to automate routine tasks or to script difficult deployments. Scripts written for the RS utility are basically VB.NET single code files. They start off by executing the Main() function. The web service endpoints are available in the script, and are referenced as the global web service proxy called RS. End users can use passed-in string variables that are available as global variables in the script. Script commands can be batched, and timeouts can be specified. The RS utility is a handy administrative and development tool. From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg CHAPTER 25 Implementing Custom Embedded Functions IN THIS CHAPTER . Adding Embedded Code . Debugging Embedded Code T he simplest form of custom code available in SSRS is expressions, which were discussed in Chapter 10, “Expressions.” The next level of coding complexity is custom embedded code in a report. Adding Embedded Code To get a better understanding of how embedded custom code is used in a report, report developers can assume all the code placed in the code window gets compiled into a make-believe class called Code . You can add properties and methods to the make-believe Code class, and call class members from expressions in the report, which has the class defined. Embedded code is compiled into a report’s intermediate format and gets executed as needed when the report is rendered. Report Designer provides a simple text area to allow editing of the embedded code. To access the code editor, complete the following steps: 1. From the Report menu, choose Report Properties. Alternatively, right-click the area surrounding the report’s body and select the Properties menu. 2. Click the Code tab in the Report Properties dialog box. You should see a window similar to that shown in Figure 25.1 and can type the code in the Custom Code area. The code editor is basically a multiline text box, and it does not provide any productivity assistance, such as IntelliSense or debugging. You have to be extremely careful while using From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 434 CHAPTER 25 Implementing Custom Embedded Functions FIGURE 25.1 Code editor. this code editor. For example, only one level of “undo” action is allowed, as compared to Visual Studio’s infinite undo. For all its difficulties, embedded code provides several key benefits for a developer, includ- ing the following: . A more elegant approach (as compared to expressions) to medium-complexity coding scenarios . A single repository for functions and methods that can be reused by multiple items within a single report, as opposed to complex copy-and-paste expressions . Direct access to the exception-handling functionality of VB.NET Every developer knows function reuse is beneficial over copy-and-paste programming. Consider the following fictitious example. Suppose two developers are assigned the paral- lel development of a single report. One developer uses embedded code, whereas the other one uses simple expressions. One of the initial goals was to highlight negative values in red. Later, this goal changed to a more complex requirement, such as color-coding numeric ranges. The developer who used embedded code could adapt to such change in requirements quickly. Embedded functions must be written in VB.NET. If you prefer C#, you would have to develop a custom assembly. This topic is covered in Chapter 26, “Creating and Calling a Custom Assembly from a Report.” From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 435 Adding Embedded Code 25 To add the function used in the preceding narrative, just follow these steps: 1. Open the report properties by either choosing Report Properties from the Report menu or right-clicking the area surrounding the report’s body and selecting Report Properties. 2. In the Report Properties dialog box, display the Code tab and enter the following function in the Custom Code area: Function Highlight(value As Integer) As String If value < 0 return “Red” Else return “Black” End If End Function 3. Drag a Textbox control from the Toolbox to the report and place the following code in the Background Color property: =Code.Highlight(me.value) 4. Place -1 (minus one) in the Value property of the text box. 5. Open the report in Preview mode to see the text box with a red background. Embedded code can address more complex scenarios. For example, if you need to calculate a median, you can use the following approach: 1. Add the following embedded code, using the method described in the previous example: Dim Data As System.Collections.ArrayList Function AddData(newData As Decimal) As Decimal If (Data is Nothing) Data = new System.Collections.ArrayList() End If Data.Add(newData) End Function Function GetMedianInfo() As String Dim count As Integer = Data.Count If (count > 0) Data.Sort() GetMedianInfo =”Median: “ & Data(count/2) & “; Total orders: “ & count End If End Function From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 436 NOTE In our sample we use the SalesOrderHeader table from the Adventure Works data- base. We will calculate the median on the TotalDue field (or median order total). Adjust the code accordingly for different fields. The query to retrieve data is very simple: SELECT TotalDue FROM Sales.SalesOrderHeader 2. Call the data set OrderTotals . 3. Add a table. (Note that in this example we use the table for calculations only, and we do not need to fill anything on the table’s surface.) 4. Select the entire table by clicking the corner handler. Set the table’s Hidden prop- erty to True . NOTE It is important to hide the table. Because of on-demand report processing enhance- ments in SSRS 2008, there is no guarantee that the Code class will maintain state across pages. You can experiment with this by making the table visible and seeing the changes in the results by applying TOP N clause to the query. 5. From the grouping pane, open Group Properties for the Details group, display the Variables tab, and enter the AddDat in the Name field and the following code in the Value field to populate Data array: =Code.AddData(Fields!TotalDue.Value) NOTE You can enter any value you want in the Name field. In the case of this example, the value that you enter for the name does not matter because we are not going to use the variable in the sample’s code. However the name is required, and SSRS will call the variable (and therefore the AddData function) every time the group variable changes. In this example, it happens for every row in the OrderTotals data set. 6. On the bottom of the report, add a text box with the following expression: =Code.GetMedianInfo() 7. Run the report and see that the median order value in the SalesOrderHeader table is $865.20 and the total number of orders is 31,465. You can take this example further and develop Excel-like functionality in terms of having calculations based on data in nonsequential Table cells, similar to =$A$1/$B$5 in Excel. CHAPTER 25 Implementing Custom Embedded Functions From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 437 Debugging Embedded Code 25 To enable the previously described calculations, we can store the values from a data set in a two-dimensional array and use the array’s members to perform calculations. Although for performance reasons we do not advocate this method on large data sets, the method can provide an elegant solution in some cases. Debugging Embedded Code SSRS does not provide any facilities to step through the embedded code, and therefore you have two options: You can either debug code in Visual Studio .NET or use some pre-Visual Basic tricks for debugging. The first trick is to label code lines. This is beneficial to locate both compile-time and runtime errors. The following code fragment shows how to label code lines. It also has errors that have been intentionally placed for demonstration purposes: Function Add(n As Integer) 1: i = i + n 2: return i End Function When you build a report with the code snippet or try to preview the report that calls this code, SSRS reports two issues (one warning and one error): . Warning: There is an error on line 0 of the custom code: [BC42021] Function without an ‘As’ clause; return type of Object assumed. Warnings display only if at least one error is found. . Error: There is an error on line 1 of the custom code: [BC30451] Name ‘i’ is not declared. Only the first error is displayed. With a small code fragment such as the preceding example, finding errors might not be an issue. For a code fragment that has a significant number of lines, locating the one with an error can prove burdensome. NOTE Keep in mind that labels can be present only inside of functions or subroutines and can repeat inside of different functions. TIP To properly determine line numbers, deliberately add an error and preview the report. The SSRS error indicates the line number. TIP To avoid laborious efforts of numbering and renumbering lines, you should only label key expressions or the first line of functions. Alternatively, you can use labeling to nar- row down a line with an error. From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 438 CHAPTER 25 Implementing Custom Embedded Functions The second trick is to locate a line that causes runtime errors by using a Try-Catch block: Function DivByZero() Dim x As Integer Try ‘ Set up structured error handling. 3: x = x/ 0 Catch ex As Exception Return ex.ToString() & vbCrLf & “Exception at Line: “ & CStr(Erl) End Try End Function The result of the call to the function DivByZero() is as follows: System.OverflowException: Arithmetic operation resulted in an overflow. at ReportExprHostImpl.CustomCodeProxy.DivByZero() Exception at Line: 3 Note that function DivByZero() uses the undocumented function Erl to return a line number for the line of code that produced the error. Erl really returns a label number. (In the preceding code, it is 3 .) When you do not implement error handling, and then make a call to a function within the Value property of a report item, the report item shows #Error as a result. Depending on the precision of a return value provided from a function, other potential results are Infinity or NaN (Not a Number). TIP Always check the Error List window after a build operation has completed, and make sure that there are no warnings. Best practice suggests eliminating all warnings in pro- duction code. Exceptions within other properties can be caught during the build operation. Summary Custom embedded code can provide a more elegant approach to medium-complexity custom code than expressions through function reuse, centralized code repository, and additional error-handling options. Custom embedded code is VB.NET code embedded in a report. Code is embedded as a part of a Report Definition Language (RDL) file and compiled together with the container report. Many errors are caught by the compiler when a reporting solution is built. From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg 439 Debugging Embedded Code 25 Although embedded code allows a developer to use the full object-oriented functionality of VB.NET, embedded code is mostly used for simple logic. It is possible to develop complex embedded code, but this is not usually done because of limited debugging facili- ties and limited functionality of the embedded code editor. The embedded code editor is a simple text box that does not have the advanced features, such as code completion, avail- able in Visual Studio. When functions are too complicated for embedded code to handle efficiently or you prefer to use C# instead of Visual Basic, you can develop and call a custom assembly from a report. The next chapter explains how to leverage a custom assembly within a report. From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ptg This page intentionally left blank From the Library of STEPHEN EISEMAN Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. [...]... directory is C:\Program Files \Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies.) This allows calling an assembly from reports in Preview mode Report Server: (The default directory is C:\Program Files \Microsoft SQL Server\ MSRS10.MSSQLSERVER\Reporting Services\ReportServer\bin.) This allows calling assembly from reports deployed on Report Server NOTE Report Designer /Server reports an error if... 453 TIP Refer to Microsoft Knowledge Base article KB842419 (http://support .microsoft. com/ ?kbid=842419) for the step-by-step process of working with security permission settings in SSRS TABLE 26.2 SSRS Configuration Files Location (Default Installation) Description rssrvpolicy.config C:\Program Files \Microsoft SQL Server\ MSRS10 MSSQLSERVER\Reporting Services\ReportServer The Report Server policy configuration... configuration file This file contains security policies for the Report Server and affects execution of the following: Custom expressions and assemblies deployed to a Report Server Custom data, delivery, rendering, and security extensions deployed to the Report Server rsmgrpolicy.config C:\Program Files \Microsoft SQL Server\ MSRS10 MSSQLSERVER\Reporting Services\ReportManager The Report Manager policy configuration... (Report Server web UI) and see how it works Let’s start at http://localhost/ReportServer (generic syntax would be http:// /ReportServer, where is a NetBIOS name, a fully qualified domain name (FQDN), or an IP address of a server on which Report Server is installed) When a developer uses Report Designer to deploy a report, the name of the project becomes the name of the folder on a Report Server. .. and the library was deployed to the SSRS binary directory (C:\Program Files \Microsoft SQL Server\ MSSQL.3\Reporting Services\ReportServer\bin\) For Report Designer, the configuration file would have changed to RSPreviewPolicy.config, and the deployment directory (and thus the value of the Url property) would be C:\Program Files \Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\RSCustomLibrary.dll... PermissionSetName=”MyPermissionSet” Name=”MyCodeGroup” Description=”A special code group for my custom assembly.”> Note that CodeGroup refers back to MyPermissionSet Alternatively, CodeGroup could have used a predefined set, such as FullTrust:... the permission: FileIOPermission permission = new FileIOPermission(FileIOPermissionAccess.Read | FileIOPermissionAccess.Write, @”C:\configuration.xml”); try { permission.Assert(); XmlDocument doc = new XmlDocument(); doc. Load(@”C:\configuration.xml”); } Alternatively, a method’s attribute can carry an assertion: [FileIOPermissionAttribute(SecurityAction.Assert, ViewAndModify= @”C:\ configuration.xml”)]... are beyond the scope of this book, a brief security overview will help you to better understand the security of SSRS assemblies You can find more security-related topics in the Microsoft NET Framework documentation (http://msdn .microsoft. com/library/default.asp?url=/library/en-us/dnnetsec/ html/netframesecover.asp) Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark From the Library... information about mscorcfg.mcs at http:/ /msdn .microsoft. com/en-us/library/2bc0cxhc.aspx and at www.emmet-gray.com/Articles/ CodeAccessSecurity.htm TIP Use the NET Framework Configuration utility (mscorcfg.mcs) to simplify permission creation and minimize the chances of malformed XML If you did not work with NET Framework 2.0 before and just installed SQL Server and Visual Studio on a “clean” machine,... Software Development Kit (SDK) from www .microsoft. com/downloads/ details.aspx?FamilyID=FE6F2099-B7B4-4F47-A244-C96D69C35DEC&displaylang=en Then you can enter mscorcfg.mcs at the SDK’s command prompt (To access the prompt, choose Start, Programs, Microsoft NET Framework SDK v2.0, SDK Command Prompt.) Alternatively, you can double-click this file in the C:\Program Files \Microsoft. NET\ SDK\v2.0\Bin directory . Files Microsoft SQL Server MSRS10.MSSQLSERVERReporting ServicesReportServerin .) This allows calling assembly from reports deployed on Report Server. . You can find more security-related topics in the Microsoft .NET Framework documentation (http://msdn .microsoft. com/library/default.asp?url=/library/en-us/dnnetsec/