Chapter 14. DataAdapters
The
DataAdapter class serves as a bridge between a
disconnected ADO.NET objects and a data source. The
DataAdapter retrieves data into a
DataSet or a DataTable from a
data source using the Fill(
)
method. Schema information can be retrieved using the
FillSchema( ) method. The
DataAdapter updates any changes made to the
DataSet or DataTable back to
the data source using the Update(
)
method.
In simple scenarios, the updating logic that the
DataAdapter uses to reconcile changes made to the
DataSet can be generated automatically from the
query used to retrieve the data by using a
CommandBuilder object. For more complex scenarios,
custom update logic can be written to control the logic the
DataAdapter uses when adding, deleting, and
modifying records in the data source in response to changes made to
the DataSet. In either case, the updating logic is
used when the Update( ) method is called.
Once data is retrieved using the DataAdapter, no
information about the connection, database, tables, columns, or any
other details about the source of the data is available in the
disconnected objects. The data can be persisted or passed between
applications without the risk of exposing details about the location
or structure of the data source or access credentials used. Figure
14-1 shows the structure of the DataAdapter and
the contained classes.
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