---
title: "Supporting Distributed Transactions | Microsoft Docs"
ms.custom: ""
ms.date: "03/14/2017"
ms.prod: sql
ms.prod_service: "database-engine, sql-database, sql-data-warehouse, pdw"
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ms.technology: native-client
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helpviewer_keywords: 
  - "OLE DB, transactions"
  - "distributed transactions [OLE DB]"
  - "MS DTC"
  - "transactions [OLE DB]"
  - "SQL Server Native Client OLE DB provider, transactions"
  - "ITransactionJoin interface"
  - "MS DTC, about distributed transaction support"
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monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-server-2016||=sqlallproducts-allversions||>=sql-server-linux-2017||=azuresqldb-mi-current"
---
# Supporting Distributed Transactions
[!INCLUDE[appliesto-ss-asdb-asdw-pdw-md](../../includes/appliesto-ss-asdb-asdw-pdw-md.md)]

  [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider consumers can use the **ITransactionJoin::JoinTransaction** method to participate in a distributed transaction coordinated by Microsoft Distributed Transaction Coordinator (MS DTC).  
  
 MS DTC exposes COM objects that allow clients to initiate and participate in coordinated transactions across multiple connections to a variety of data stores. To initiate a transaction, the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider consumer uses the MS DTC **ITransactionDispenser** interface. The **BeginTransaction** member of **ITransactionDispenser** returns a reference on a distributed transaction object. This reference is passed to the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider using **JoinTransaction**.  
  
 MS DTC supports asynchronous commit and abort on distributed transactions. For notification on asynchronous transaction status, the consumer implements the **ITransactionOutcomeEvents** interface and connects the interface to an MS DTC transaction object.  
  
 For distributed transactions, the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider implements **ITransactionJoin::JoinTransaction** parameters as follows.  
  
|Parameter|Description|  
|---------------|-----------------|  
|*punkTransactionCoord*|A pointer to an MS DTC transaction object.|  
|*IsoLevel*|Ignored by the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider. The isolation level for MS DTC-coordinated transactions is determined when the consumer acquires a transaction object from MS DTC.|  
|*IsoFlags*|Must be 0. The [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider returns XACT_E_NOISORETAIN if any other value is specified by the consumer.|  
|*POtherOptions*|If not NULL, the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider requests the options object from the interface. The [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider returns XACT_E_NOTIMEOUT if the options object's *ulTimeout* member is not zero. The [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB provider ignores the value of the *szDescription* member.|  
  
 This example coordinates transaction by using MS DTC.  
  
```  
// Interfaces used in the example.  
IDBCreateSession*       pIDBCreateSession   = NULL;  
ITransactionJoin*       pITransactionJoin   = NULL;  
IDBCreateCommand*       pIDBCreateCommand   = NULL;  
IRowset*                pIRowset            = NULL;  
  
// Transaction dispenser and transaction from MS DTC.  
ITransactionDispenser*  pITransactionDispenser = NULL;  
ITransaction*           pITransaction       = NULL;  
  
    HRESULT             hr;  
  
// Get the command creation interface for the session.  
if (FAILED(hr = pIDBCreateSession->CreateSession(NULL,  
     IID_IDBCreateCommand, (IUnknown**) &pIDBCreateCommand)))  
    {  
    // Process error from session creation. Release any references and  
    // return.  
    }  
  
// Get a transaction dispenser object from MS DTC and  
// start a transaction.  
if (FAILED(hr = DtcGetTransactionManager(NULL, NULL,  
    IID_ITransactionDispenser, 0, 0, NULL,  
    (void**) &pITransactionDispenser)))  
    {  
    // Process error message from MS DTC, release any references,  
    // and then return.  
    }  
if (FAILED(hr = pITransactionDispenser->BeginTransaction(  
    NULL, ISOLATIONLEVEL_READCOMMITTED, ISOFLAG_RETAIN_DONTCARE,  
    NULL, &pITransaction)))  
    {  
    // Process error message from MS DTC, release any references,  
    // and then return.  
    }  
  
// Join the transaction.  
if (FAILED(pIDBCreateCommand->QueryInterface(IID_ITransactionJoin,  
    (void**) &pITransactionJoin)))  
    {  
    // Process failure to get an interface, release any references, and  
    // then return.  
    }  
if (FAILED(pITransactionJoin->JoinTransaction(  
    (IUnknown*) pITransaction, 0, 0, NULL)))  
    {  
    // Process join failure, release any references, and then return.  
    }  
  
// Get data into a rowset, then update the data. Functions are not  
// illustrated in this example.  
if (FAILED(hr = ExecuteCommand(pIDBCreateCommand, &pIRowset)))  
    {  
    // Release any references and return.  
    }  
  
// If rowset data update fails, then terminate the transaction, else  
// commit. The example doesn't retain the rowset.  
if (FAILED(hr = UpdateDataInRowset(pIRowset, bDelayedUpdate)))  
    {  
    // Get error from update, then abort.  
    pITransaction->Abort(NULL, FALSE, FALSE);  
    }  
else  
    {  
    if (FAILED(hr = pITransaction->Commit(FALSE, 0, 0)))  
        {  
        // Get error from failed commit.  
        //  
        // If a distributed commit fails, application logic could  
        // analyze failure and retry. In this example, terminate. The   
        // consumer must resolve this somehow.  
        pITransaction->Abort(NULL, FALSE, FALSE);  
        }  
    }  
  
if (FAILED(hr))  
    {  
    // Update of data or commit failed. Release any references and  
    // return.  
    }  
  
// Un-enlist from the distributed transaction by setting   
// the transaction object pointer to NULL.  
if (FAILED(pITransactionJoin->JoinTransaction(  
    (IUnknown*) NULL, 0, 0, NULL)))  
    {  
    // Process failure, and then return.  
    }  
  
// Release any references and continue.  
```  
  
## See Also  
 [Transactions](../../relational-databases/native-client-ole-db-transactions/transactions.md)