IDataAdapter.Update(DataSet) Method

Reference

Definition

Namespace:: System.Data

Assembly:: System.Data.Common.dll

Assembly:: System.Data.dll

Assembly:: netstandard.dll

Important

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Calls the respective INSERT, UPDATE, or DELETE statements for each inserted, updated, or deleted row in the specified DataSet from a DataTable named "Table".

public:
 int Update(System::Data::DataSet ^ dataSet);

public int Update (System.Data.DataSet dataSet);

abstract member Update : System.Data.DataSet -> int

Public Function Update (dataSet As DataSet) As Integer

Parameters

dataSet: DataSet

The DataSet used to update the data source.

Returns

Int32

The number of rows successfully updated from the DataSet.

Exceptions

DBConcurrencyException

An attempt to execute an INSERT, UPDATE, or DELETE statement resulted in zero records affected.

Examples

The following example uses the derived class, OleDbDataAdapter, to Update the data source. This example assumes that you have created an OleDbDataAdapter and a DataSet.

static private DataSet CreateCommandAndUpdate(
    string connectionString,
    string queryString)
{
    DataSet dataSet = new DataSet();

    using (OleDbConnection connection =
               new OleDbConnection(connectionString))
    {
        connection.Open();
        OleDbDataAdapter adapter =
            new OleDbDataAdapter();
        adapter.SelectCommand =
            new OleDbCommand(queryString, connection);
        OleDbCommandBuilder builder =
            new OleDbCommandBuilder(adapter);

        adapter.Fill(dataSet);

        // Code to modify data in the DataSet here.

        // Without the OleDbCommandBuilder, this line would fail.
        adapter.UpdateCommand = builder.GetUpdateCommand();
        adapter.Update(dataSet);
    }
    return dataSet;
}

Public Function CreateCommandAndUpdate( _
    ByVal connectionString As String, _
    ByVal queryString As String) As DataSet

    Dim dataSet As New DataSet()

    Using connection As New OleDbConnection(connectionString)
        connection.Open()
        Dim adapter As New OleDbDataAdapter()

        adapter.SelectCommand = New OleDbCommand( _
            queryString, connection)

        Dim builder As OleDbCommandBuilder = _
            New OleDbCommandBuilder(adapter)

        adapter.Fill(dataSet)

        ' Code to modify the data in the DataSet here. 

        ' Without the OleDbCommandBuilder this line would fail.
        builder.GetUpdateCommand()
        adapter.Update(dataSet)
    End Using
    Return dataSet
End Function

Remarks

When an application calls the Update method, the IDataAdapter examines the RowState property, and executes the required INSERT, UPDATE, or DELETE statements iteratively for each row, based on the order of the indexes configured in the DataSet. For example, Update might execute a DELETE statement, followed by an INSERT statement, and then another DELETE statement, because of the ordering of the rows in the DataTable.

Be aware that these statements are not performed as a batch process; each row is updated individually. An application can call the GetChanges method if you must control the sequence of statement types (for example, INSERTs before UPDATEs). For more information, see Updating Data Sources with DataAdapters.

If INSERT, UPDATE, or DELETE statements have not been specified, the Update method generates an exception. However, you can create a SqlCommandBuilder or OleDbCommandBuilder object to automatically generate SQL statements for single-table updates if you set the SelectCommand property of a .NET Framework data provider. Then, any additional SQL statements that you do not set are generated by the CommandBuilder. This generation logic requires key column information to be present in the DataSet. For more information see Generating Commands with CommandBuilders.

The Update method retrieves rows from the table listed in the first mapping before performing an update. The Update then updates the row using the value of the UpdatedRowSource property. Any additional rows returned are ignored.

After any data is loaded back into the DataSet, the OnRowUpdated event is raised, allowing the user to inspect the reconciled DataSet row and any output parameters returned by the command. After a row updates successfully, the changes to that row are accepted.

When using Update, the order of execution is as follows:

The values in the DataRow are moved to the parameter values.
The OnRowUpdating event is raised.
The command executes.
If the command is set to FirstReturnedRecord, then the first returned result is put in the DataRow.
If there are output parameters, they are put in the DataRow.
The OnRowUpdated event is raised.
AcceptChanges is called.

Each command associated with the IDataAdapter usually has a parameter collection associated with it. Parameters are mapped to the current row through the SourceColumn and SourceVersion properties of a .NET Framework data provider's Parameter class. SourceColumn refers to a DataTable column that the IDataAdapter references to obtain parameter values for the current row.

SourceColumn refers to the unmapped column name before any table mappings have been applied. If SourceColumn refers to a nonexistent column, the action taken depends on one of the following MissingMappingAction values.

Enumeration Value	Action Taken
`MissingMappingAction.Passthrough`	Use the source column names and table names in the DataSet if no mapping is present.
`MissingMappingAction.Ignore`	A SystemException is generated. When the mappings are explicitly set, a missing mapping for an input parameter is usually caused by an error.
`MissingMappingAction.Error`	A SystemException is generated.

The SourceColumn property is also used to map the value for output or input/output parameters back to the DataSet. An exception is generated if it refers to a nonexistent column.

The SourceVersion property of a .NET Framework data provider's Parameter class determines whether to use the Original, Current, or Proposed version of the column value. This capability is frequently used to include original values in the WHERE clause of an UPDATE statement to check for optimistic concurrency violations.

Note

If an error occurs while updating a row, an exception is thrown and execution of the update is discontinued. To continue the update operation without generating exceptions when an error is encountered, set the ContinueUpdateOnError property to true before calling Update. You may also respond to errors on a per-row basis within the RowUpdated event of a DataAdapter. To continue the update operation without generating an exception within the RowUpdated event, set the Status property of the RowUpdatedEventArgs to Continue.

Applies to

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