29.1 Comments/Troubleshooting
No reference is maintained between the DataSet,
the DataAdapter, and the Connection.
After the DataAdapter retrieves data from a data
source into a DataSet, the
DataSet has no information about the connection,
database, tables, columns, or any other details about the source of
the data.
Because the DataAdapter is a connected class, each
.NET data provider implements its own DataAdapter,
with a similar interface and function to other
DataAdapter classes but in its own unique
namespace. The DataAdapter class namespaces for
several ADO.NET data providers are listed in Table 29-1.
Table 29-1. Provider-specific DataAdapter classes
System.Data.SqlClient.SqlDataAdapter
|
SQL Server
|
System.Data.OleDb.OleDbDataAdapter
|
OLE DB provider
|
Microsoft.Data.Odbc.OdbcDataAdapter
|
ODBC driver
|
System.Data.OracleClient.OracleDataAdapter
|
Oracle
|
The commonly used public properties of the
DataAdapter class are listed in Table 29-2.
Table 29-2. DataAdapter properties
AcceptChangesDuringFill
|
Gets or sets a value indicating whether the row is committed when
added to a table using the Fill( ) method.
|
ContinueUpdateOnError
|
Gets or sets a value indicating whether the
DataAdapter should raise an exception and stop
processing remaining updates when an error is encountered.
|
DeleteCommand
|
Gets or sets the command, either a SQL statement or a stored
procedure, that deletes the DataSet records marked
for deletion from the data source when using the Update(
) method.
|
InsertCommand
|
Gets or sets the command, either a SQL statement or a stored
procedure, that inserts new DataSet records into
the data source when using the Update( ) method.
|
MissingMappingAction
|
Specifies the action to take when columns or tables in the incoming
data from the data source don't have matching
columns or tables in the DataSet.
|
MissingSchemaAction
|
Specifies the action to take when the schema of the data source
doesn't match the DataSet schema.
|
SelectCommand
|
Gets or sets the command, either a SQL statement or a stored
procedure, that selects records from the data source when using the
Fill( ) method.
|
UpdateCommand
|
Gets or sets the command, either a SQL statement or a stored
procedure, that updates modified Dataset records
in the data source when using the Update( )
method.
|
The commonly used public collections of the
DataAdapter class are listed in Table 29-3.
Table 29-3. DataAdapter collections
TableMappings
|
Accesses the DataTableMappingCollection, which
contains table and column name mapping information for reconciling
the disconnected data with the data source, as a collection of
DataTableMapping objects.
|
The commonly used public methods of the
DataAdapter class are listed in Table 29-4.
Table 29-4. DataAdapter methods
Fill( )
|
Adds new rows or refreshes rows in the DataSet
with data from the data source.
|
FillSchema( )
|
Adds an empty table to the DataSet and configures
its schema to match the data source.
|
GetFillParameters( )
|
Returns an array of parameter objects for the
SelectCommand.
|
Update( )
|
Submits changes in the DataSet to the data source
for reconciliation.
|
The commonly used public events of the DataAdapter
class are listed in Table 29-5.
Table 29-5. DataAdapter events
FillError
|
Raised when an error is encountered during a Fill(
) operation.
|
RowUpdating
|
Raised before the command to reconcile a DataSet
row with the data source row has been executed.
|
RowUpdated
|
Raised after the command to reconcile a DataSet
row with the data source row has been executed.
|
The DataAdapter class inherits from
Component and implements the
IDataAdapter interface. Public static members of
this class are safe for multithreaded operations; instance members
aren't guaranteed to be thread-safe.
|
