Propriedade do RDL SqlCeCommand.Transaction

Artigo
05/27/2011

Obtém ou define a transação na qual o SqlCeCommand é executado.

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

Sintaxe

'Declaração
Public Property Transaction As SqlCeTransaction
    Get
    Set
'Uso
Dim instance As SqlCeCommand
Dim value As SqlCeTransaction

value = instance.Transaction

instance.Transaction = value

public SqlCeTransaction Transaction { get; set; }

public:
property SqlCeTransaction^ Transaction {
    SqlCeTransaction^ get ();
    void set (SqlCeTransaction^ value);
}

member Transaction : SqlCeTransaction with get, set

function get Transaction () : SqlCeTransaction
function set Transaction (value : SqlCeTransaction)

Valor da propriedade

Tipo: System.Data.SqlServerCe.SqlCeTransaction
A SqlCeTransaction. O valor padrão é nulluma referência nula (Nothing no Visual Basic).

Comentários

Não será possível definir a propriedade Transaction se ela já estiver definida com um valor específico e o comando esteja em processo de execução. Se você definir a propriedade transaction de um objeto SqlCeTransaction que não está conectado à mesma SqlCeConnection que o objeto SqlCeCommand, será lançada uma exceção da próxima vez que uma instrução for executada.

Se o SqlCeCommand for executado com SqlCeTransaction definida como nulluma referência nula (Nothing no Visual Basic), o comando será executado no modo de confirmação automática; assim, cada instrução será executada em sua própria transação.

Exemplos

Dim conn As New SqlCeConnection("Data Source = MyDatabase.sdf; Password ='<pwd>'")
conn.Open()

' Start a local transaction
'
Dim tx As SqlCeTransaction = conn.BeginTransaction()

' By default, commands run in auto-commit mode; 
'
Dim cmd1 As SqlCeCommand = conn.CreateCommand()

' You may create multiple commands on the same connection
'
Dim cmd2 As SqlCeCommand = conn.CreateCommand()

' To enlist a command in a transaction, set the Transaction property
'
cmd1.Transaction = tx

Try
    cmd1.CommandText = "INSERT INTO Shippers ([Company Name]) VALUES ('Northwind Traders')"
    cmd1.ExecuteNonQuery()

    ' Auto-commited because cmd2 is not enlisted in a transaction
    '
    cmd2.CommandText = "INSERT INTO Employees ([Last Name], [First Name]) VALUES ('Decker', 'Barbara')"
    cmd2.ExecuteNonQuery()

    ' This will cause referential constraint violation
    '
    cmd1.CommandText = "DELETE FROM Products WHERE [Product ID] = 1"
    cmd1.ExecuteNonQuery()

    ' Commit the changes to disk if everything above succeeded
    '
    tx.Commit()
Catch
    tx.Rollback()
Finally
    conn.Close()
End Try

SqlCeConnection conn = new SqlCeConnection("Data Source = MyDatabase.sdf; Password ='<pwd>'");
conn.Open();

// Start a local transaction
//
SqlCeTransaction tx = conn.BeginTransaction();

// By default, commands run in auto-commit mode; 
//
SqlCeCommand cmd1 = conn.CreateCommand();

// You may create multiple commands on the same connection
//
SqlCeCommand cmd2 = conn.CreateCommand();

// To enlist a command in a transaction, set the Transaction property
//
cmd1.Transaction = tx;

try
{
    cmd1.CommandText = "INSERT INTO Shippers ([Company Name]) VALUES ('Northwind Traders')";
    cmd1.ExecuteNonQuery();

    // Auto-commited because cmd2 is not enlisted in a transaction
    //
    cmd2.CommandText = "INSERT INTO Employees ([Last Name], [First Name]) VALUES ('Decker', 'Barbara')";
    cmd2.ExecuteNonQuery();

    // This will cause referential constraint violation
    //
    cmd1.CommandText = "DELETE FROM Products WHERE [Product ID] = 1";
    cmd1.ExecuteNonQuery();

    // Commit the changes to disk if everything above succeeded
    //
    tx.Commit();
}
catch (Exception)
{
    tx.Rollback();
}
finally
{
    conn.Close();
}

Consulte também

Referência

SqlCeCommand Classe

Namespace System.Data.SqlServerCe

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