Reporting Services: Difference between RDL and RDLC files

Microsoft Reporting Services is an enterprise-capable reporting solution that can be used to create all types of reports such as Production, Analytical, and Dashboard. Building reports is done through Business Intelligence Development Studio which is an extension of Visual Studio. Reports are created as RDL (Report Definition Language) files. Once the reports are created with BIDS, they (RDLs) are hosted in Reporting Services and users can be accessed them in many ways.

What are RDLC files?
RDLC: Report Definition Language, Client Side files are files that are generated with either ReportViewer Control that comes with Visual Studio 2008 Windows or ASP.NET project templates, or Reporing –> Report Application project template. It is a XML file, just like the RDL. It uses the same XML schema that is used by RDL files but RDLC does not require to have values for all elements such as query text. If RDLC file is needed to be hosted in Reporting Services, it needs to be renamed as RDL and all empty elements must be filled manually.

Reporting with ReportViewer Control
The ReportViewer Control allows us to embed a report to ASP.NET web page or Windows form. It supports two modes: Remote Processing mode and Local Processing mode. The Remote Processing mode allows to connect with reports that have been already deployed to SSRS instance. In this case, all the processing take place at the SSRS server. The Local Processing mode allows to create reports within Visual Studio itself. The extension of them are RDLC. This does not require an instance of Reporting Services, hence processing is handled by the client application.

Here are some of important points to remember about these two modes:

• Local Processing mode does not require an instance of Reporting Services, hence a license for Reporting Services is not required.
• Local Processing mode is not recommended for large reports. It is used for small, OLTP types of reports. They may run infrequently.
• Remote Processing can be scaled out but Local Processing.
• Local Processing mode supports following extensions only:
• Visual Studio 2008: PDF and Excel
• Visual Studio 2010: PDF, Excel and Word
• Local Processing mode with Visual Studio 2008 does not support Tablix data region. Visual Studio 2010 supports.
• Mapping parameters with query parameters has to be done manually with Local Processing mode.