Propriedade do RDL SqlCeDataAdapter.DeleteCommand

Artigo
05/27/2011

Obtém ou define uma instrução SQL para excluir registros do conjunto de dados.

Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (em System.Data.SqlServerCe.dll)

Sintaxe

'Declaração
Public Property DeleteCommand As SqlCeCommand
    Get
    Set
'Uso
Dim instance As SqlCeDataAdapter
Dim value As SqlCeCommand

value = instance.DeleteCommand

instance.DeleteCommand = value

public SqlCeCommand DeleteCommand { get; set; }

public:
property SqlCeCommand^ DeleteCommand {
    SqlCeCommand^ get ();
    void set (SqlCeCommand^ value);
}

member DeleteCommand : SqlCeCommand with get, set

function get DeleteCommand () : SqlCeCommand
function set DeleteCommand (value : SqlCeCommand)

Valor da propriedade

Tipo: System.Data.SqlServerCe.SqlCeCommand
Um SqlCeCommand usado durante a Update para excluir registros da fonte de dados que correspondem às linhas excluídas do DataSet.

Comentários

Durante uma chamada para Update, se esta propriedade não estiver definida e as informações da chave primária estiverem presentes no DataSet, DeleteCommand poderá ser gerado automaticamente, se você definir a propriedade SelectCommand e usar o SqlCeCommandBuilder. Então, todos os comandos adicionais que não forem definidos serão gerados pelo SqlCeCommandBuilder. Essa lógica de geração exige que as informações da coluna de chave estejam presentes no DataSet.

Quando DeleteCommand for atribuído a um SqlCeCommand criado anteriormente, o SqlCeCommand não será clonado. O DeleteCommand mantém uma referência ao objeto SqlCeCommand criado anteriormente.

Exemplos

O exemplo a seguir cria um SqlCeDataAdapter e define algumas de suas propriedades.

Dim cmd As SqlCeCommand = Nothing
Dim adp As SqlCeDataAdapter = Nothing

Try
    adp = New SqlCeDataAdapter()
    Dim conn As New SqlCeConnection("Data Source = MyDatabase.sdf")

    ' Create the SelectCommand
    '
    cmd = conn.CreateCommand()
    cmd.CommandText = "SELECT * FROM Orders WHERE [Ship Country] = @country AND [Ship City] = @city"
    cmd.Parameters.Add("@country", SqlDbType.NVarChar, 15)
    cmd.Parameters.Add("@city", SqlDbType.NVarChar, 15)

    cmd.Parameters("@country").Value = "UK"
    cmd.Parameters("@city").Value = "London"

    adp.SelectCommand = cmd

    ' Create the DeleteCommand
    '
    cmd = conn.CreateCommand()
    cmd.CommandText = "DELETE FROM Orders WHERE [Order ID] = @orderID"

    Dim p As SqlCeParameter = cmd.Parameters.Add("@orderID", SqlDbType.NChar, 5, "Order ID")
    p.SourceVersion = DataRowVersion.Original

    adp.DeleteCommand = cmd

    ' Populate the dataset with the results from the SELECT statement
    '
    Dim ds As New DataSet()
    adp.Fill(ds)

    ' Modify the dataset
    '
    MessageBox.Show("Number of rows: " & ds.Tables(0).Rows.Count)

    ' Delete some rows
    '
    ds.Tables(0).Rows(3).Delete()
    ds.Tables(0).Rows(4).Delete()

    ' This will execute two DELETE statements 
    '
    adp.Update(ds.Tables(0))
Catch e As Exception
    MessageBox.Show(e.Message)
Finally
    If Not Nothing Is adp.SelectCommand Then
        adp.SelectCommand.Dispose()
    End If
    If Not Nothing Is adp.DeleteCommand Then
        adp.DeleteCommand.Dispose()
    End If
End Try

SqlCeCommand cmd = null;
SqlCeDataAdapter adp = null;

try
{
    adp = new SqlCeDataAdapter();
    SqlCeConnection conn = new SqlCeConnection("Data Source = MyDatabase.sdf");

    // Create the SelectCommand
    //
    cmd = conn.CreateCommand();
    cmd.CommandText = "SELECT * FROM Orders WHERE [Ship Country] = @country AND [Ship City] = @city";
    cmd.Parameters.Add("@country", SqlDbType.NVarChar, 15);
    cmd.Parameters.Add("@city", SqlDbType.NVarChar, 15);

    cmd.Parameters["@country"].Value = "UK";
    cmd.Parameters["@city"].Value = "London";

    adp.SelectCommand = cmd;

    // Create the DeleteCommand
    //
    cmd = conn.CreateCommand();
    cmd.CommandText = "DELETE FROM Orders WHERE [Order ID] = @orderID";

    SqlCeParameter p = cmd.Parameters.Add("@orderID", SqlDbType.NChar, 5, "Order ID");
    p.SourceVersion = DataRowVersion.Original;

    adp.DeleteCommand = cmd;

    // Populate the dataset with the results from the SELECT statement
    //
    DataSet ds = new DataSet();
    adp.Fill(ds);

    // Modify the dataset
    //
    MessageBox.Show("Number of rows: " + ds.Tables[0].Rows.Count);

    // Delete some rows
    //
    ds.Tables[0].Rows[3].Delete();
    ds.Tables[0].Rows[4].Delete();

    // This will execute two DELETE statements 
    //
    adp.Update(ds.Tables[0]);
}
catch (Exception e)
{
    MessageBox.Show(e.Message);
}
finally
{
    if (null != adp.SelectCommand) adp.SelectCommand.Dispose();
    if (null != adp.DeleteCommand) adp.DeleteCommand.Dispose();
}

Consulte também

Referência

SqlCeDataAdapter Classe

Namespace System.Data.SqlServerCe

InsertCommand

SelectCommand

UpdateCommand

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