To begin, we need to understand the distinction between query and report parameters.
A query parameter is passed to the data query engine to be incorporated into
the SQL script's WHERE clause or some other part of the SQL that can accept
parameters. A report parameter is passed to the report processor to be processed
while the report is rendered on the client. Both types of parameters are stored
in the report definition (the RDL file), where you can manage them by using
the Report namespace. It's a useful exercise to examine the RDL (or RDLC) file
to see how parameters are defined in the XML. Take a look at Figure
3—it shows a snippet of an RDL report definition that defines the
report parameters. The Report Parameters dialog box that Figure
2 shows is used to define and (optionally) to set default, permissible values
and other parameter attributes.