Databases Reference
In-Depth Information
a group. These options cause more data to be sent to the report server but may help prevent
multiple, long-running queries if users spend time interacting with a single report.
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Parameters may be used to drive advanced report features such as cascading parameter selection.
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SQL Server Analysis Services may be used to simplify complex report queries by storing preag-
gregated values in multidimensional cubes.
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The MDX Query Designer may be used to define data sets for Analysis Service queries and
related parameters with little or no understanding of the MDX query language.
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Reports may use many different data sources that use different SQL dialects and query languages.
Any data source may be used as long as it supports an ODBC driver, OLE DB provider, or .NET
data provider that returns rows and columns or data.
Defining data sources and data sets to manage data source queries is the starting point for almost any
data-driven report. It's essential to understand basic data storage and query architecture to achieve the
best design. Data can be filtered within the database server or in the report. Making the correct choice
and finding the best combination of these options will improve performance and provide flexibility with
the least degree of overhead.
Defining shared data sources in your projects makes it much easier to maintain data connections for all
of your reports as a group. Changing the database location or security credentials becomes a much sim-
pler proposition. The data sets for your reports define queries for retrieving data and may be used as the
source for the report and repeatable data regions or to provide data value for report parameters.
An ad hoc query expression is stored in the report within the report definition, and a stored procedure
is stored in the database. Using stored procedures is an effective means for processing parameters and
filtering data before sending it to the report, while using a report filter lets you reuse the data you've
already retrieved. A combination of these parameterized filtering techniques may be an optimal solution
for more complex reporting needs.
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