SqlCeConnection.BeginTransaction-Methode (IsolationLevel)

Artikel
05/27/2011

Beginnt eine Datenbanktransaktion mit dem aktuellen IsolationLevel-Wert.

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

Syntax

'Declaration
<SecurityTreatAsSafeAttribute> _
<SecurityCriticalAttribute> _
<SecurityPermissionAttribute(SecurityAction.Assert, UnmanagedCode := True)> _
Public Function BeginTransaction ( _
    isolationLevel As IsolationLevel _
) As SqlCeTransaction
'Usage
Dim instance As SqlCeConnection
Dim isolationLevel As IsolationLevel
Dim returnValue As SqlCeTransaction

returnValue = instance.BeginTransaction(isolationLevel)

[SecurityTreatAsSafeAttribute]
[SecurityCriticalAttribute]
[SecurityPermissionAttribute(SecurityAction.Assert, UnmanagedCode = true)]
public SqlCeTransaction BeginTransaction(
    IsolationLevel isolationLevel
)

[SecurityTreatAsSafeAttribute]
[SecurityCriticalAttribute]
[SecurityPermissionAttribute(SecurityAction::Assert, UnmanagedCode = true)]
public:
SqlCeTransaction^ BeginTransaction(
    IsolationLevel isolationLevel
)

[<SecurityTreatAsSafeAttribute>]
[<SecurityCriticalAttribute>]
[<SecurityPermissionAttribute(SecurityAction.Assert, UnmanagedCode = true)>]
member BeginTransaction : 
        isolationLevel:IsolationLevel -> SqlCeTransaction

public function BeginTransaction(
    isolationLevel : IsolationLevel
) : SqlCeTransaction

Parameter

isolationLevel
Typ: System.Data.IsolationLevel
Die Transaktionsisolationsstufe für diese Verbindung.

Rückgabewert

Typ: System.Data.SqlServerCe.SqlCeTransaction
Ein Objekt, das die neue Transaktion darstellt.

Hinweise

Sie müssen für die Transaktion mit der Commit-Methode oder der Rollback-Methode einen expliziten Commit oder Rollback ausführen.

Beispiele

Im folgenden Beispiel werden eine SqlCeConnection-Klasse und eine SqlCeTransaction-Klasse erstellt. Anschließend wird die Verwendung der BeginTransaction-Methode, der Commit-Methode und der Rollback-Methode veranschaulicht.

Dim conn As New SqlCeConnection("Data Source = AdventureWorks.sdf;")
conn.Open()

' Start a local transaction; SQL Mobile supports the following 
' isolation levels: ReadCommitted, RepeatableRead, Serializable
'
Dim tx As SqlCeTransaction = conn.BeginTransaction(IsolationLevel.ReadCommitted)

' 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 FactSalesQuota " & _
        "(EmployeeKey, TimeKey, SalesAmountQuota) " & _
        "VALUES (2, 1158, 150000.00)"

    cmd1.ExecuteNonQuery()

    ' Auto-commited because cmd2 is not enlisted in a transaction
    '
    cmd2.CommandText = "INSERT INTO FactSalesQuota " & _
        "(EmployeeKey, TimeKey, SalesAmountQuota) " & _
        "VALUES (3, 1157, 15000.00)"

    cmd2.ExecuteNonQuery()

    ' Commit the changes to disk if everything above succeeded;
    ' Use Deferred mode for optimal performance; the changes will 
    ' be flashed to disk within the timespan specified in the 
    ' ConnectionString 'FLUSH INTERVAL' property; 
    '
    tx.Commit(CommitMode.Deferred)

    ' Alternatively, you could use:
    ' tx.Commit(CommitMode.Immediate);
    '
    ' or use default (Deferred) commit mode:
    ' tx.Commit()

Catch e As Exception
    ' Handle errors here
    '
    tx.Rollback()
Finally
    conn.Close()
End Try

SqlCeConnection conn = new SqlCeConnection("Data Source = AdventureWorks.sdf;");
conn.Open();

// Start a local transaction; SQL Mobile supports the following 
// isolation levels: ReadCommitted, RepeatableRead, Serializable
//
SqlCeTransaction tx = conn.BeginTransaction(IsolationLevel.ReadCommitted);

// 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 FactSalesQuota " +
        "(EmployeeKey, TimeKey, SalesAmountQuota) " +
        "VALUES (2, 1158, 150000.00)";

    cmd1.ExecuteNonQuery();

    // Auto-commited because cmd2 is not enlisted in a transaction
    //
    cmd2.CommandText = "INSERT INTO FactSalesQuota " +
        "(EmployeeKey, TimeKey, SalesAmountQuota) " +
        "VALUES (3, 1157, 15000.00)";

    cmd2.ExecuteNonQuery();

    // Commit the changes to disk if everything above succeeded;
    // Use Deferred mode for optimal performance; the changes will 
    // be flashed to disk within the timespan specified in the 
    // ConnectionString 'FLUSH INTERVAL' property; 
    //
    tx.Commit(CommitMode.Deferred);

    // Alternatively, you could use:
    // tx.Commit(CommitMode.Immediate);
    //
    // or use default (Deferred) commit mode:
    // tx.Commit()
}
catch (Exception)
{
    // Handle errors here
    //
    tx.Rollback();
}
finally
{
    conn.Close();
}