Introduction
This Interview Questions will give you a quick start for two report giant's crystal and reporting services.
How do we access crystal reports in .NET?
Crystal reports comes with Visual studio setup itself. Right click the solution explorer a add new item and you can see a crystal report template as shown in figure "Crystal report template". You can add an ".rpt" file using this template.
Figure 1:- Crystal report template
What are the various components in crystal reports?
There are four major components in crystal reports Report designer, Reports engine, Report viewer and object models.
Report designer gives a graphical interface to create and modify reports. To view the designer add a new crystal report file and double click on it you should see the report designer as shown in figure "Report designer".
Figure 2 :- Report designer
Reports engine does the formatting and conversion part of crystal reports. It helps convert the contents of reports in word, excel, PDF, HTML and other formats. Report viewers are controls which you can see on the visual studio tool box; you can drag and drop those controls on an ASPX page or windows application to view reports made using crystal. Object models help us manage crystal reports objects during design time and run time.
What basic steps are needed to display a simple report in crystal?
To understand this sample let display a simple report using crystal.
Step1:- Create a web application project.
Step2:- Add new item and select crystal report from the template. This adds a new RPT file in your solution explorer.
Step3 :- Double click on the RPT file click on Crystal reports a Field explorer as shown in figure below. You should see the field explorer toolbar.
Figure 3:- Field explorer toolbar
Step 4 a Right click on "Database fields" on the field explorer a then click on database expert a Expand create new connection a Expand OLE DB ADO a Select Microsoft OLEDB provider for SQL Server ( this depends on what kind of data you want to connect ) a Give the server credentials a Click finish and done.
Step5 a Right click on "Database fields" on the field explorer a then click on database expert a Expand the server , database and select table which you want to add to the report. Below figure "Table added in reports" shows the right pane showing the table added using database expert.
Figure 4 :- Table added in reports
Step 6 a Expand database fields a table ( in this case it is "FactCurrencyRate" table). Now you can drag and drop the fields on the report.
Figure 5 : - Drag fields on the report
Step 7 a We now need to display the report on the ASPX page. For that we need the "CrystalReportViewer" control. So expand the crystal reports section of the toolbar and drag the component on the ASPX page
Figure 6 : - "Crystalreportviewer" control
Step 8:- Now we need to go to code behind and specify the report source. That's it now compile and run the project you can see your report live in action.
Figure 7 : - Specify the crystal report source
Can crystal reports be published as a web service?
Right click on the "RPT" file and click "Publish as web service" as shown in figure "Publish crystal as web service".
Figure 8 : - Publish Crystal as web service
How do we invoke the crystal report web service?
We can consume the web service as a normal web service in .NET. The easiest way is by using the "ReportViewerControl" and specifying the ASMX URL in the report source property.
How do we add formulas using crystal reports?
To add any formula in crystal report is a three step procedure. Below figure "Add formula in crystal report" shows the three steps in a pictorial format. Step 1 a Go to field explorer and right click and click new formula. Step 2 a Give and name to the formulae and click on "Use Editor". Step 3 a You will be presented with UI which has all the formulas and function.
Figure 9 : - Add formula in crystal report
How do we pass parameters to crystal reports?
Some times we want to accept input parameter and the report works according to the parameter. To add a input parameter go to field explorer , go to parameter fields , right click , create parameter and you should be popped with a dialog box as shown in the figure "Parameter field". Give a name to the parameter , type and that's it you are in action.
Figure 10 :- Parameter fields
How do we export from crystal reports?
There are two way of using the export option one is when we display a report using crystal report viewer you can see a export icon as shown in figure "Export" below. You can the select in which format you want to export.
Figure 11 : - Export
Second option is through coding. Below is a simple code snippet which shows how we can export a report. Create a object of the crystal report and call the "ExportToDisk" method specifying in which format you want to export.
Dim Report as New CrystalReport1
Report.ExportToDisk(CrystalDecisions.Shared.ExportFormatType.WordForWindows,"c:\my.doc")
How do we print to printer using crystal?
In print we have two ways by which we can print one is when you display the report using crystal report viewer you have a print option and second is by code. Below is a simple code snippet which shows how we have created a object called as report from the rpt file , specified the printer name , paper size and then called the "PrintToPrinter" method.
Report.PrintOptions.PrinterName = "MyPrinter"
Report.PrintOptions.PaperSize = CrystalDecisions.Shared.PaperSize.PaperA4
Report.PrintOptions.PaperOrientation = CrystalDecisions.Shared.PaperOrientation.Landscape
Report.PrintToPrinter(1, True, 1, 3)
How do we generate cross tab reports?
When we go for creating a new report you can see the cross tab option.
Figure 12 : - Cross tab reports
How can we do grouping in crystal?
For grouping in crystal you need to use the group expert wizard.
Can you explain three-pass reporting which crystal report uses?
Crystal report uses the three pass method for parsing reports. Before we understand what does it means lets define what is a pass ?. Pass is a process used by crystal reports to read and manipulate data as per the report format. Below figure "Three pass method" shows how the parsing happens. Let's understand the same step by step. In Pre-Pass1 crystal report engine evaluates constants like x=1 and pie=3.14 for a report. Pass 1 does two important things get data from the database and sort records with given conditions. Once this is done it's saved in memory and given to pre-pass2 for further parsing and manipulation. Pre-pass2 is all about grouping and sorting the records according to conditions specified in the crystal report. Pass 2 formats a report, applies condition and groups them. Pass 3 is the final tunnel it just counts the pages and generates reports.
Figure 13 :- Three pass method
Can you explain reporting services architecture?
Reporting services is mainly used to generate reports. Below are the main components of reporting services as shown in figure "Reporting Services Architecture". Reporting services has four major components Client, Web services, report server/manager and reporting services database. Let's understand all the major components and the sub components of the same.
Figure 14 : - Reporting Services Architecture
Client: - These are the consumers of reporting services functionality. It can be the report manager or report server (we will discuss report server and manager in more details further) or ASPX and windows application.
Reporting Web service: - Microsoft chose XML to expose the functionality of reporting services. So all the functionality is exposed through web services. One of the most important gains for a web service is that it can be platform independent.
Report server / manager: - Report server and manager forms the core engine of reporting services. They two important systems one is "Report processor" and the other is
"Scheduling and Delivery processor". Reporting processor is the main driver to deliver reports. They take request from the end user and process the report and send it to the end client. Figure "Report Processor" shows how the flow moves. We have seven basic steps which can help us understand in more detail how the report processor works.
Step 1 a Any client like ASPX or windows application will request to the web service for reports.
Step 2 and 3 a Web service will forward the request to the report processor and get the report definition from the report server DB.
Step 4 a Reporting services uses the
security extensions to authenticate the end user.
Step 5 a
Data processing extension calls queries the application database to get data. With data processing extension we can connect to standard data sources like SQL Server, ODBC, Oracle etc. You can also extend the data processing extension to adapt it to some custom data processing extension.
Step 6 a
Rendering extension then renders the report applies format and sends the same to the end client. Using rendering extension you can deliver reports in Excel, PDF, HTML, CSV and XML. You can also extend the rendering extension to deliver in custom formats.
Figure 15 : - Report Processor
The second system is "Scheduling and Delivery processor".
Delivery extensions makes reports with the specified format and sends the same to an output target like file, email, FTP etc. Scheduling and delivery processor does two important steps schedules reports and delivers them the same to a output like FTP,Email etc. Schedule and delivery processor using delivery extension to deliver reports to the defined output. So users can subscribe to the reports and depending on these subscriptions the delivery is done by schedule and delivery processor. There are two steps in this one is the subscription process and the other is deliver process. Lets first try to understand the subscription process. There are three steps basically:-
Step 1 a First is the requests a subscription to the report.
Step 2a This subscription is then stored in the report server DB.
Step 3 a A new SQL Server agent is created for this subscription. So we have completed the subscription process.
Figure 16 : - Subscription process
Now that the subscription is created lets see how the delivery process works. Here are five basic steps in delivery process. Step 1 a When the event occurs SQL Server agent makes an entry in the report server DB. Step 2 and 3 a RS windows service keeps polling SQL Server for any events. If a event has occurred it gets the event from the database and sends a message to the "Scheduling and Delivery Processor". Step 4 a The report is then processed by the report processor and sent to the delivery extension who finally delivers it on a output which can be a email address, folder, FTP or any other kind of output.
Figure 17 : - Delivery process
Reporting Services Database:- When you install reporting services you will see two databases "ReportServer" and "ReportServerTempDB"."ReportServer" database contains report definitions, schedule, subscriptions, security details and snapshots. "ReportServerTempDB" stores temporary information like session state about reports which is needed in between HTTP requests and report cache information.
Please note snapshots are stored in reportserver and not in tempDB.
Figure 18 :- Databases of reporting services
We have two IIS application ‘Reports’ and ‘Reportserver’ what do they do ?
When you install reporting services there are two virtual directories created as shown in the figure below.
Figure : - IIS Applications for reports
The ‘Reports’ virtual directory is like an admin. If you browse to http://yourpcname/reports/home.aspx page you can view, edit properties and display reports. We have numbered the below figure. 1 à We can browse reports and see the output of reports. 2 à We can upload a RDL file directly in the report’s database. 3 à Using the report builder link we build new reports. 4 à Using the properties we can do role assignment. 5 à Using subscription link we can add new outputs (FTP, Folder etc) to subscribe to the reports. 6 à Site settings help us to decide how many numbers of snapshots we want in the history, report time out execution, report execution logging, scheduling, manage jobs and security settings.
Figure :- Reports Admin
The second virtual directory is the ‘ReportServer’ this helps us to use browse reports and use the same in ASP.NET code using URL methodology , try browsing to http://yourpcname/reportserver/ you can easily figure out what this virtual directory is all about.
Can you explain Report definition language (RDL) file in reporting services?
RDL is an XML description of a report in reporting services. So basically the RDL file has the XML grammar which describes a reporting services report. Below figure ‘Snip of RDL file’ shows a simple snippet of a RDL file.
Figure : - Snip of RDL file
What is the basic process of making a report in reporting services?
Here are the basic steps which will help you in creating reports in reporting services:-
- Open Visual studio 2005 à File à New project à Select ‘Business Intelligence Reports’ à Select Report Server project.
- When the project is created in the solution explorer you will see two folder ‘Shared data resources’ ( we will come to data sources in the coming questions) and ‘Reports’. Right click the ‘Reports’ folder and click add new reports.
- You need to give credentials in the wizard. Once done it pops up a query builder. Specify the report query in the query builder and go next.
- Wizard then helps you to select the report type and some other features. Next , next and you should see a RDL file in your ‘Reports’ folder.
- Click on the view menu and select tool box and you should be able to design the report.
- Till now we are only in the design mode of report. As said previously all reports meta-data are stored in SQL Server database ‘ReportServer’. In order that the report’s meta-data gets saved in database we need to publish the report.
- To publish the report we need to specify the IIS report path. So right click on the report project, select properties and specify the ‘TargetServerURL’ property.
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Figure :- TargetServerURL property
- Once we have specified the ‘TargetServerURL’ property we need to deploy the project. So right click on project and click ‘Deploy’
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Figure : - Deploying reports
- You can now view your report using http://localhost/Reports/Pages/Folder.aspx URL.
How can we consume reports in ASP.NET?
There are three famous ways of calling reporting services report in ASP.NET:-
- Using URL way to access reports.
- Using reporting web service to programmatically access reports.
- Using report viewer control.
URL way
This is the most basic way of accessing reports. We specify the URL as shown below which then displays the report on the browser. Below is a basic format of how to display a report using the URL methodology. 1 à This is the IIS report application. 2 à This is the project name or the project folder in which the report resides. 3 à This is the report name. 4 à This is the command to the reporting service of what to do. In this case we are saying render the report.
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Figure : - Basic URL
If we want to get the report in PDF format we need to use the ‘Format’ parameter.
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Figure : - Generate the report in PDF format
If we want to pass parameters to the report we can do something as shown in the figure ‘Pass parameters to the report’. In this scenario we have passed the ‘Category’ parameter.
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Figure : - Pass parameters to the report
Consuming reporting services web service
If you look at the architecture of reporting service all reports are exposed through XML i.e. Web services.You can see the web service using this URL http://localhost/ReportServer/ReportService2005.asmx. In localhost you need to put the server name or IP address. So below are the steps to display reports using web service.
Step 1 à First add the web service using http://localhost/ReportServer/ReportService2005.asmx in your ASP.NET project.
Step 2 à We need to consume the web service and use it. Below is the code snippet which shows how the reporting service object is used. 1 à You can see the web service references to ‘reportservice2005.asmx’. 2 à We have the named the web service as ‘Localhost’, so you can see we have imported the web service. 3 à We need to create object of ‘ReportingService2005’ class. 4 à We need to set the credentials of the reporting object. 5 à In this we will display which reports are present in the reporting server database. So we use the ‘ListChildren’ method to get the reports from the web service and then loop to display the same. 6 à This sample code should display the reports present in the reporting service.
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Figure : - Display reports in reporting server
The above example is a sample of how to use the reporting web service. If you want to get how many input parameters the report has we need to use ‘GetReportParameters’ method, if we want to display the report we use the ‘Render’ function. There are many other function and methods which we have not discussed to keep the chapter simple and to the point. Please experiment around the reporting web service object for new methods and functions.
Reportviewer control
ASP.NET 2.0 comes with crystal report viewer control. You can drag and drop the control on the ASPX page and set the properties. Below figure shows how the ‘ReportviewerControl’ looks like and how we can set the properties to view the report.
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Figure :- ReportViewerControl in action
Can you explain the difference between private and shared data sources?
Private data source is used by single report only while shared data sources are shared between reports. As a practice it is good to have shared data source so if you want to change anything you need to change only on one data source.
How does reports caching in reporting services work ?
As said previously reporting services has two main databases ‘ReportServer’ and ‘ReportServerTempDB’. Below figure ‘Reporting Services Caching’ shows how caching works in reporting services. Client first sends a request to the reporting service for report. Reporting processor gets data from the database and the report format from the ‘reportserver’ database. Both these elements are then used to create ‘Intermediate report format’. This intermediate format is saved in ‘ReportServerTempDB’. This intermediate format is for a particular user and for a session. So if the user generates the same report he will get a cached version. If the report is having parameters then there are different cached versions of report for every parameter combination. Cached versions expire after particular schedule, when reports are modified, deleted or redeployed.
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Figure : - Reporting services Caching
In order to set the caching properties browse to a particular report using http://localhost/reports/ à click on properties à and go to execution tab. Below figure ‘Caching options’ shows different conditions on which you can define caching strategy.
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Figure :- Caching strategy
What are the major differences between Crystal and SQL reporting services?
Ease of hosting reports: - Using the URL technology in RS we can host reports more easily than in crystal report where we need to make a UI for the same.
Supporting platforms: - Crystal can run on windows, IBM and sun while RS (reporting services) can run only on windows environment.
Client tools: - In reporting services we have Business intelligence ( BI ) and development studio while in crystal its Report designer.
Caching: - This achieved in crystal by using cache server while in reporting services it’s stored as snapshots in Reportserver database.
Export formats:- In crystal we have HTML,PDF,Excel,XML,Word , PDF , RTF , CSV, text files while in SQL Server 2005 we have all the formats above it also gives capability to extend custom reporting formats.
Data sources:- Crystal support more data sources while RS only supports Microsoft and oracle data sources. Crystal supports ADO, COM, Database excel Access, Exchange, NT, Xbase, JDBC, File system and Paradox. RS supports only SQL Server, Oracle, ODBC, OLEDB and you can also extend additional data sources which does not exists in crystal reports.
Version issues: - One of the main issues faced in crystal is it have different versions which makes it difficult to use, while RS comes with SQL Server minimizing the version issue.
Web server support: - Crystal can run on IIS 5/6, Apache, lotus etc while RS works only with IIS 5.0 and above.