Propriedade do RDL SqlCeDataAdapter.UpdateCommand
Obtém ou define uma instrução SQL usada para atualizar registros na fonte de dados.
Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (em System.Data.SqlServerCe.dll)
Sintaxe
'Declaração
Public Property UpdateCommand As SqlCeCommand
Get
Set
'Uso
Dim instance As SqlCeDataAdapter
Dim value As SqlCeCommand
value = instance.UpdateCommand
instance.UpdateCommand = value
public SqlCeCommand UpdateCommand { get; set; }
public:
property SqlCeCommand^ UpdateCommand {
SqlCeCommand^ get ();
void set (SqlCeCommand^ value);
}
member UpdateCommand : SqlCeCommand with get, set
function get UpdateCommand () : SqlCeCommand
function set UpdateCommand (value : SqlCeCommand)
Valor da propriedade
Tipo: System.Data.SqlServerCe.SqlCeCommand
Um SqlCeCommand usado durante a Update para atualizar registros da fonte de dados que correspondem às linhas modificadas do DataSet.
Comentários
Durante a Update, se esta propriedade não estiver definida e as informações da chave primária estiverem presentes no DataSet, o UpdateCommand poderá ser gerado automaticamente. Para que essa propriedade seja gerada automaticamente, defina a propriedade SelectCommand e use 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 UpdateCommand for atribuído a um SqlCeCommand criado anteriormente, o SqlCeCommand não será clonado. O UpdateCommand mantém uma referência ao objeto SqlCeCommand criado anteriormente.
Dica
Se a execução deste comando retornar linhas, essas linhas podem ser mescladas ao DataSet, dependendo de como é definida a propriedade UpdatedRowSource do objeto SqlCeCommand.
Exemplos
O exemplo a seguir cria um SqlCeDataAdapter, modifica um conjunto de dados e chama o método Update para atualizar a fonte de dados.
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 [Employee ID], [First Name], [Last Name] FROM Employees"
adp.SelectCommand = cmd
' Create the InsertCommand
'
cmd = conn.CreateCommand()
cmd.CommandText = "INSERT INTO Employees ([First Name],[Last Name]) VALUES (@first, @last)"
Dim p As SqlCeParameter = Nothing
p = cmd.Parameters.Add("@first", SqlDbType.NVarChar, 10, "First Name")
p.SourceVersion = DataRowVersion.Original
p = cmd.Parameters.Add("@last", SqlDbType.NVarChar, 20, "Last Name")
p.SourceVersion = DataRowVersion.Original
adp.InsertCommand = cmd
' Create the UpdateCommand
'
cmd = conn.CreateCommand()
cmd.CommandText = "UPDATE Employees SET [First Name] = @first, " + _
"[Last Name] = @last WHERE [Employee ID] = @employeeID"
p = cmd.Parameters.Add("@first", SqlDbType.NVarChar, 10, "First Name")
p.SourceVersion = DataRowVersion.Current
p = cmd.Parameters.Add("@last", SqlDbType.NVarChar, 20, "Last Name")
p.SourceVersion = DataRowVersion.Current
p = cmd.Parameters.Add("@employeeID", SqlDbType.NVarChar, 20, "Employee ID")
p.SourceVersion = DataRowVersion.Original
adp.UpdateCommand = 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)
' Insert some rows
'
ds.Tables(0).Rows.Add(New Object() {Nothing, "Barbara", "Decker"})
ds.Tables(0).Rows.Add(New Object() {Nothing, "Joe", "Clayton"})
' Update some rows
'
ds.Tables(0).Rows(1)(1) = "David"
ds.Tables(0).Rows(1)(2) = "Johnson"
' This will execute two INSERT and one UPDATE 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.InsertCommand Then
adp.InsertCommand.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 [Employee ID], [First Name], [Last Name] FROM Employees";
adp.SelectCommand = cmd;
// Create the InsertCommand
//
cmd = conn.CreateCommand();
cmd.CommandText = "INSERT INTO Employees ([First Name],[Last Name]) VALUES (@first, @last)";
SqlCeParameter p = null;
p = cmd.Parameters.Add("@first", SqlDbType.NVarChar, 10, "First Name");
p.SourceVersion = DataRowVersion.Original;
p = cmd.Parameters.Add("@last", SqlDbType.NVarChar, 20, "Last Name");
p.SourceVersion = DataRowVersion.Original;
adp.InsertCommand = cmd;
// Create the UpdateCommand
//
cmd = conn.CreateCommand();
cmd.CommandText = "UPDATE Employees SET [First Name] = @first, " +
"[Last Name] = @last WHERE [Employee ID] = @employeeID";
p = cmd.Parameters.Add("@first", SqlDbType.NVarChar, 10, "First Name");
p.SourceVersion = DataRowVersion.Current;
p = cmd.Parameters.Add("@last", SqlDbType.NVarChar, 20, "Last Name");
p.SourceVersion = DataRowVersion.Current;
p = cmd.Parameters.Add("@employeeID", SqlDbType.NVarChar, 20, "Employee ID");
p.SourceVersion = DataRowVersion.Original;
adp.UpdateCommand = 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);
// Insert some rows
//
ds.Tables[0].Rows.Add(new object[] { null, "Barbara", "Decker" });
ds.Tables[0].Rows.Add(new object[] { null, "Joe", "Clayton" });
// Update some rows
//
ds.Tables[0].Rows[1][1] = "David";
ds.Tables[0].Rows[1][2] = "Johnson";
// This will execute two INSERT and one UPDATE statements
//
adp.Update(ds.Tables[0]);
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
finally
{
if (null != adp.SelectCommand) adp.SelectCommand.Dispose();
if (null != adp.InsertCommand) adp.InsertCommand.Dispose();
}