Query Designers and Data Processing Extensions
On a Reporting Services report authoring client, data processing extensions and data providers are associated in the RSReportDesigner.config file with a query designer. Reporting Services provides several types of query designers. When you select a data source in Report Designer, the associated query designer opens, ready to help you design a query for this type of data source.
You must use a query designer to define a query for retrieving data from a report data source. Typical query designers can be based on text or graphics. With a text-based query designer, you type command text into a query pane. With a graphical query designer, you drag metadata items that represent the underlying data on a data source to the query design surface. Most multidimensional data sources provide a graphical query designer that displays metadata representing the data on the data source. You can change from a graphical query designer to a text-based query designer by clicking the generic query designer () icon on the toolbar. You can only change from a text-based query designer to a graphical query designer if one is registered for that data source. Because not all valid queries can be represented in a graphical query designer, when you switch query designer modes, your query text is not necessarily preserved. To have the most control over the query text, use the generic query designer.
The following examples illustrate query command text that can be affected by the data provider:
Support for the schema part of a database object name. When a data source uses schemas as part of the database object identifier, the schema name must be supplied as part of the query for any names that do not use the default schema. For example,
SELECT FirstName, LastName FROM [Person].[Contact].
Support for query parameters. Data providers differ in support for parameters. Some data providers support named parameters; for example,
SELECT Col1, Col2 FROM Table WHERE <parameter identifier><parameter name> = <value>. Some data providers support unnamed parameters; for example,
SELECT Col1, Col2 FROM Table WHERE <column name> = ?. The parameter identifier may differ by data provider; for example, SQL Server uses the "at" (@) symbol, Oracle uses the colon (:) . Some data providers do not support parameters. For more information, see Data Sources Supported by Reporting Services.
For more information about query designers, see Data View (Report Designer) and Visual Database Tool Designers (Visual Database Tools).