Difference between .rdl and .rdlc file

Difference between rdl and rdlc:

·         The <Query> element of RDL contains query or command information and is used by the report server to connect to the data sources of the report.

·         The <Query> element is optional in an RDLC file. This element is ignored by the ReportViewer control because the ReportViewer control does not perform any data processing in local processing mode, but uses data that the host application supplies.

·         Report Viewer’s dataset is different from rdl’s dataset.

• Dataset and data source terminology has different meanings in Visual Studio 2005 and SQL Server 2005. In Visual Studio, a dataset is a collection of data tables and is logically equivalent to a query or command that retrieves data. In Reporting Services, a dataset includes the following parts:
• Data source information, including the data source type and connection string. The data source type specifies a data processing extension that is deployed on the report server.
• Credential information that specifies how to obtain credentials for the data source connection.
• Query or command information used to retrieve data.

Visually, an .rdlc file that is configured to run in a ReportViewer control has the dataset object, binding source object, and table object displayed at the bottom of the designer view. The following diagram provides an illustration of how these objects appear in a Windows form (the same data binding objects appear differently in a Web page):

If you select an .rdlc file for use in a ReportViewer control and the data objects do not appear in the project, you are most likely looking at a renamed .rdl file that requires additional conversion steps to make it a fully functional .rdlc file.

The dataset name might be misleading; by default, Reporting Services uses the name of the data source for the first dataset that is created (for example, a dataset might be called "Northwind" even if it only retrieves data from one of the tables).