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在 SQL Server Native Client 中設定大型數據

適用於:SQL Server Azure SQL 資料庫 Azure SQL 受控執行個體 Azure Synapse Analytics Platform System (PDW)

透過 SQL Server Native Client OLE DB 提供者,您可以將指標傳遞至取用者記憶體對象來設定 BLOB 數據。

取用者會建立包含資料的儲存物件,並將此儲存物件的指標傳遞給提供者。 接著,提供者會從取用者儲存物件讀取資料,並將其寫入到 BLOB 資料行。

若要傳遞自己的儲存物件指標,取用者會建立一個繫結 BLOB 資料行值的存取子。 然後,取用者會利用繫結 BLOB 資料行的存取子,呼叫 IRowsetChange::SetDataIRowsetChange::InsertRow 方法。 它會在取用者的儲存物件上傳遞儲存介面的指標。

本主題會參考可供下列函數使用的功能:

  • IRowset:SetData

  • ICommand::Execute

  • IRowsetUpdate::Update

如何設定大型資料

若要傳遞自己的儲存物件指標,取用者會建立一個繫結 BLOB 資料行值的存取子,然後呼叫 IRowsetChange::SetDataIRowsetChange::InsertRow 方法。 設定 BLOB 資料:

  1. 建立一個 DBOBJECT 結構,描述如何存取 BLOB 資料行。 將 DBOBJECT 結構的 dwFlag 項目設定為 STGM_READ,並將 iid 項目設定為 IID_ISequentialStream (要公開的介面)。

  2. 在 DBPROPSET_ROWSET 屬性群組中設定屬性,讓資料列集可以更新。

  3. 使用 DBBINDING 結構的陣列來建立一組繫結 (每個資料行一個)。 將 DBBINDING 結構中的 wType 項目設定為 DBTYPE_IUNKNOWN,並將 pObject 項目設定為指向您所建立的 DBOBJECT 結構。

  4. 使用繫結資訊,在結構的 DBBINDINGS 陣列中建立存取子。

  5. 呼叫 GetNextRows 將下一個資料列擷取到資料列集中。 呼叫 GetData 來讀取資料列集中的資料。

  6. 建立包含資料 (以及長度指標) 的儲存物件,然後使用繫結 BLOB 資料行來設定資料的存取子,呼叫 IRowsetChange::SetData (或 IRowsetChange::InsertRow)。

範例

這個範例會示範如何設定 BLOB 資料。 此範例會建立一個資料表、加入範例記錄、在資料列集中提取該記錄,然後設定 BLOB 欄位的值:

#define UNICODE  
#define DBINITCONSTANTS  
#define INITGID  
  
#include <windows.h>  
#include <stdio.h>  
#include <stddef.h>  
#include <iostream.h>  
  
#include <oledb.h>  
#include <oledberr.h>  
  
#include <sqlncli.h>  
  
#define SAFE_RELEASE(pIUnknown) if(pIUnknown) (pIUnknown)->Release();  
HRESULT GetCommandObject(REFIID riid, IUnknown** ppIUnknown);  
HRESULT CreateTable(ICommandText* pICommandText);  
  
class CSeqStream : public ISequentialStream  
{  
public:  
    //Constructors  
    CSeqStream();  
    virtual ~CSeqStream();  
  
    virtual BOOL Seek(ULONG iPos);  
    virtual BOOL Clear();  
    virtual BOOL CompareData(void* pBuffer);  
    virtual ULONG Length()  { return m_cBufSize; };  
  
    virtual operator void* const() { return m_pBuffer; };  
  
    STDMETHODIMP_(ULONG)    AddRef(void);  
    STDMETHODIMP_(ULONG)    Release(void);  
    STDMETHODIMP QueryInterface(REFIID riid, LPVOID *ppv);  
  
    STDMETHODIMP Read(   
            /* [out] */ void __RPC_FAR *pv,  
            /* [in]  */ ULONG cb,  
            /* [out] */ ULONG __RPC_FAR *pcbRead);  
  
    STDMETHODIMP Write(   
            /* [in] */ const void __RPC_FAR *pv,  
            /* [in] */ ULONG cb,  
            /* [out]*/ ULONG __RPC_FAR *pcbWritten);  
  
protected:  
    //Data  
  
private:  
  
    ULONG       m_cRef;         // reference count  
    void*       m_pBuffer;      // buffer  
    ULONG       m_cBufSize;     // buffer size  
    ULONG       m_iPos;         // current index position in the buffer  
};  
  
//class implementation  
  
CSeqStream::CSeqStream()  
{  
    m_iPos         = 0;  
    m_cRef         = 0;  
    m_pBuffer      = NULL;  
    m_cBufSize     = 0;  
  
    //The constructor AddRef's  
    AddRef();  
}  
  
CSeqStream::~CSeqStream()  
{  
    //Shouldn't have any references left  
//    ASSERT(m_cRef == 0);  
    CoTaskMemFree(m_pBuffer);  
}  
  
ULONG    CSeqStream::AddRef(void)  
{  
    return ++m_cRef;  
}  
  
ULONG    CSeqStream::Release(void)  
{  
//    ASSERT(m_cRef);  
  
    if(--m_cRef)  
        return m_cRef;  
  
    delete this;  
    return 0;  
}  
  
HRESULT CSeqStream::QueryInterface(REFIID riid, void** ppv)  
{  
//    ASSERT(ppv);  
    *ppv = NULL;  
  
    if (riid == IID_IUnknown)  
        *ppv = this;  
    if (riid == IID_ISequentialStream)  
        *ppv = this;  
  
    if(*ppv)  
    {  
        ((IUnknown*)*ppv)->AddRef();  
        return S_OK;  
    }  
  
    return E_NOINTERFACE;  
}  
  
BOOL CSeqStream::Seek(ULONG iPos)  
{  
    // Make sure the desired position is within the buffer.  
//    ASSERT(iPos == 0 || iPos < m_cBufSize);  
  
    // Reset the current buffer position.  
    m_iPos = iPos;  
    return TRUE;  
}  
  
BOOL CSeqStream::Clear()  
{  
    //Frees the buffer  
    m_iPos         = 0;  
    m_cBufSize     = 0;  
  
    CoTaskMemFree(m_pBuffer);  
    m_pBuffer = NULL;  
  
    return TRUE;  
}  
  
BOOL CSeqStream::CompareData(void* pBuffer)  
{  
//    ASSERT(pBuffer);  
  
    // Quick and easy way to compare user buffer with the stream.  
    return memcmp(pBuffer, m_pBuffer, m_cBufSize)==0;  
}  
  
HRESULT CSeqStream::Read(void *pv, ULONG cb, ULONG* pcbRead)  
{  
    //Parameter checking  
    if(pcbRead)  
        *pcbRead = 0;  
  
    if(!pv)  
        return STG_E_INVALIDPOINTER;  
  
    if(cb == 0)  
        return S_OK;  
  
    // Actual code.  
    ULONG cBytesLeft = m_cBufSize - m_iPos;  
    ULONG cBytesRead = cb > cBytesLeft ? cBytesLeft : cb;  
  
    // If no more bytes to retrieve return.  
    if(cBytesLeft == 0)  
        return S_FALSE;   
  
    // Copy to users buffer the number of bytes requested or remaining.  
    memcpy_s(pv, sizeof(pv), (void*)((BYTE*)m_pBuffer + m_iPos), cBytesRead);  
    m_iPos += cBytesRead;  
  
    if(pcbRead)  
        *pcbRead = cBytesRead;  
  
    if(cb != cBytesRead)  
        return S_FALSE;   
  
    return S_OK;  
}  
  
HRESULT CSeqStream::Write(const void *pv, ULONG cb, ULONG* pcbWritten)  
{  
    // Parameter checking.  
    if(!pv)  
        return STG_E_INVALIDPOINTER;  
  
    if(pcbWritten)  
        *pcbWritten = 0;  
  
    if(cb == 0)  
        return S_OK;  
  
    // Enlarge the current buffer.  
    m_cBufSize += cb;  
  
    // Need to append to the end of the stream.  
    m_pBuffer = CoTaskMemRealloc(m_pBuffer, m_cBufSize);  
    memcpy_s((void*)((BYTE*)m_pBuffer + m_iPos), sizeof((void*)((BYTE*)m_pBuffer + m_iPos)), pv, cb);  
    // m_iPos += cb;  
  
    if(pcbWritten)  
        *pcbWritten = cb;  
  
    return S_OK;  
}  
//...........................................................  
void main()  
{  
    CoInitialize(NULL);  
  
    DBOBJECT ObjectStruct;  
    ObjectStruct.dwFlags = STGM_READ;  
    ObjectStruct.iid     = IID_ISequentialStream;  
  
    struct BLOBDATA  
    {  
        DBSTATUS            dwStatus;     
        DWORD               dwLength;   
        ISequentialStream*  pISeqStream;  
    };  
  
    BLOBDATA BLOBGetData;  
    BLOBDATA BLOBSetData;  
  
    const ULONG cBindings = 1;  
    DBBINDING rgBindings[cBindings];   
    HRESULT hr = S_OK;  
    IAccessor*          pIAccessor          = NULL;  
    ICommandText*       pICommandText       = NULL;  
    ICommandProperties* pICommandProperties = NULL;  
    IRowsetChange*      pIRowsetChange      = NULL;  
    IRowset*            pIRowset            = NULL;  
    CSeqStream*         pMySeqStream        = NULL;  
    ULONG cRowsObtained = 0;  
    HACCESSOR hAccessor = DB_NULL_HACCESSOR;  
    DBBINDSTATUS rgBindStatus[cBindings];  
    HROW* rghRows = NULL;  
    const ULONG cPropSets = 1;  
    DBPROPSET   rgPropSets[cPropSets];  
    const ULONG cProperties = 1;  
    DBPROP      rgProperties[cProperties];  
    const ULONG cBytes = 10;  
    BYTE        pBuffer[cBytes];  
    ULONG       cBytesRead = 0;  
  
    BYTE pReadData[cBytes];  //read BLOB data in this array  
    memset(pReadData, 0xAA, cBytes);  
  
    BYTE pWriteData[cBytes];  //write BLOB data from this array  
    memset(pWriteData, 'D', cBytes);  
  
    // Get the Command object.  
    hr = GetCommandObject(IID_ICommandText,   
                          (IUnknown**)&pICommandText);  
    if (FAILED(hr))  
    {  
        cout << "Failed to get ICommandText interface.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    // Create table with image column and index.  
    hr = CreateTable(pICommandText);  
    if (FAILED(hr))  
    {  
        cout << "Failed to create table.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    /*  
    Set the DBPROPSET structure.  It is used to pass an array   
    of DBPROP structures to SetProperties().  
    */  
    rgPropSets[0].guidPropertySet = DBPROPSET_ROWSET;  
    rgPropSets[0].cProperties = cProperties;  
    rgPropSets[0].rgProperties = rgProperties;  
  
    // Now set properties in the property group (DBPROPSET_ROWSET).  
    rgPropSets[0].rgProperties[0].dwPropertyID = DBPROP_UPDATABILITY;  
    rgPropSets[0].rgProperties[0].dwOptions = DBPROPOPTIONS_REQUIRED;  
    rgPropSets[0].rgProperties[0].dwStatus = DBPROPSTATUS_OK;  
    rgPropSets[0].rgProperties[0].colid = DB_NULLID;  
    rgPropSets[0].rgProperties[0].vValue.vt = VT_I4;  
    V_I4(&rgPropSets[0].rgProperties[0].vValue) = DBPROPVAL_UP_CHANGE;  
  
    // Set the rowset properties.  
    hr = pICommandText->QueryInterface(IID_ICommandProperties,  
                            (void **)&pICommandProperties);  
    if (FAILED(hr))  
    {  
        cout << "Failed to get ICommandProperties to set rowset properties.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
    hr = pICommandProperties->SetProperties(cPropSets, rgPropSets);  
    if (FAILED(hr))  
    {  
        cout << "Execute failed to set rowset properties.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    // Execute a command (SELECT * FROM TestISeqStream).  
    hr = pICommandText->SetCommandText(DBGUID_DBSQL,  
                                       L"SELECT * FROM TestISeqStream");  
    if (FAILED(hr))  
    {  
        cout << "Failed to set command text SELECT * FROM.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    hr = pICommandText->Execute(NULL, IID_IRowsetChange, NULL, NULL,  
                                (IUnknown**)&pIRowsetChange);  
    if (FAILED(hr))  
    {  
        cout << "Failed to execute the command SELECT * FROM.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    // Fill the DBBINDINGS array.  
    rgBindings[0].iOrdinal = 2; //ordinal position  
    rgBindings[0].obValue = offsetof(BLOBDATA, pISeqStream);  
    rgBindings[0].obLength = offsetof(BLOBDATA, dwLength);  
    rgBindings[0].obStatus = offsetof(BLOBDATA, dwStatus);  
    rgBindings[0].pTypeInfo = NULL;  
    rgBindings[0].pObject = &ObjectStruct;  
    rgBindings[0].pBindExt = NULL;  
    rgBindings[0].dwPart =  DBPART_VALUE | DBPART_STATUS | DBPART_LENGTH;  
    rgBindings[0].dwMemOwner = DBMEMOWNER_CLIENTOWNED;  
    rgBindings[0].eParamIO = DBPARAMIO_NOTPARAM;  
    rgBindings[0].cbMaxLen = 0;   
    rgBindings[0].dwFlags = 0;  
    rgBindings[0].wType = DBTYPE_IUNKNOWN;  
    rgBindings[0].bPrecision = 0;  
    rgBindings[0].bScale = 0;  
  
    // Create an accessor using the binding information.  
    hr = pIRowsetChange->QueryInterface(IID_IAccessor,   
                                        (void**)&pIAccessor);  
    if (FAILED(hr))  
    {  
        cout << "Failed to get IAccessor interface.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    hr = pIAccessor->CreateAccessor(DBACCESSOR_ROWDATA,  
                                    cBindings,  
                                    rgBindings,   
                                    sizeof(BLOBDATA),  
                                    &hAccessor,  
                                    rgBindStatus);  
    if (FAILED(hr))  
    {  
        cout << "Failed to create an accessor.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if   
  
    // Now get the first row.  
    hr = pIRowsetChange->QueryInterface(IID_IRowset,   
                                        (void **)&pIRowset);  
    if (FAILED(hr))  
    {  
        cout << "Failed to get IRowset interface.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    hr = pIRowset->GetNextRows(NULL,   
                               0,   
                               1,   
                               &cRowsObtained,   
                               &rghRows);  
  
    hr = pIRowset->GetData(rghRows[0],   
                           hAccessor,   
                           &BLOBGetData);  
  
    // Verify the retrieved data, only if data is not null.  
    if (BLOBGetData.dwStatus == DBSTATUS_S_ISNULL)  
    {  
        // Process null data.  
        cout << "Provider returned a null value.\n";  
    } else if(BLOBGetData.dwStatus == DBSTATUS_S_OK)   
      // Provider returned a nonNULL value.  
    {  
        BLOBGetData.pISeqStream->Read(  
                                    pBuffer,   
                                    cBytes,   
                                    &cBytesRead);  
        if(memcmp(pBuffer, pReadData, cBytes) != 0)  
        {  
            //cleanup   
         }  
  
        SAFE_RELEASE(BLOBGetData.pISeqStream);  
    }  
  
    // Set up data for SetData.  
    pMySeqStream = new CSeqStream();  
  
    /*  
    Put data in to the ISequentialStream object   
    for the provider to write.  
    */  
    pMySeqStream->Write(pWriteData,   
                        cBytes,   
                        NULL);  
  
    BLOBSetData.pISeqStream = (ISequentialStream*)pMySeqStream;  
    BLOBSetData.dwStatus    = DBSTATUS_S_OK;  
    BLOBSetData.dwLength    = pMySeqStream->Length();  
  
    // Set the data.  
    hr = pIRowsetChange->SetData(rghRows[0],   
                                 hAccessor,   
                                 &BLOBSetData);  
        if (FAILED(hr))  
    {  
        cout << "Failed to set data.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    hr = pIAccessor->ReleaseAccessor(hAccessor, NULL);  
    if (FAILED(hr))  
    {  
        cout << "Failed to release accessor.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
    hr = pIRowset->ReleaseRows(cRowsObtained,   
                            rghRows,   
                            NULL,   
                            NULL,   
                            NULL);  
    if (FAILED(hr))  
    {  
        cout << "Failed to release rows.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
Exit:  
    // Free up all allocated memory and release interface pointers.  
  
    CoUninitialize();  
} //end main.  
//..........................................................  
HRESULT GetCommandObject(REFIID riid, IUnknown** ppIUnknown)  
{  
    HRESULT hr = S_OK;  
  
    // Local interface pointers, until a connection is made.  
    IDBInitialize* pIDBInitialize = NULL;  
    IDBProperties*  pIDBProperties = NULL;  
    IDBCreateSession* pIDBCreateSession = NULL;  
    IDBCreateCommand* pIDBCreateCommand = NULL;  
  
    const ULONG cPropSets = 1;  
    DBPROPSET rgPropSets[cPropSets];  
  
    const ULONG cProperties = 4;  
    DBPROP rgProperties[cProperties];  
  
    /*  
    Initialize the property values needed to   
    establish the connection.  
    */  
    for(ULONG i = 0; i < 4; i++)  
        VariantInit(&rgProperties[i].vValue);  
  
    // Server name.  
    rgProperties[0].dwPropertyID = DBPROP_INIT_DATASOURCE;  
    rgProperties[0].vValue.vt = VT_BSTR;  
    rgProperties[0].vValue.bstrVal =   
                    SysAllocString(L"server");  
    rgProperties[0].dwOptions = DBPROPOPTIONS_REQUIRED;  
    rgProperties[0].colid = DB_NULLID;  
  
    // Database.  
    rgProperties[1].dwPropertyID = DBPROP_INIT_CATALOG;  
    rgProperties[1].vValue.vt = VT_BSTR;  
    rgProperties[1].vValue.bstrVal =   
                    SysAllocString(L"pubs");  
    rgProperties[1].dwOptions = DBPROPOPTIONS_REQUIRED;  
    rgProperties[1].colid = DB_NULLID;  
  
    // Username (login).  
    rgProperties[2].dwPropertyID = DBPROP_AUTH_USERID;  
    rgProperties[2].vValue.vt = VT_BSTR;  
    rgProperties[2].vValue.bstrVal =   
                    SysAllocString(L"login");  
    rgProperties[2].dwOptions = DBPROPOPTIONS_REQUIRED;  
    rgProperties[2].colid = DB_NULLID;  
  
    // Password.  
    rgProperties[3].dwPropertyID = DBPROP_AUTH_PASSWORD;  
    rgProperties[3].vValue.vt = VT_BSTR;  
    rgProperties[3].vValue.bstrVal =   
                    SysAllocString(L"password");  
    rgProperties[3].dwOptions = DBPROPOPTIONS_REQUIRED;  
    rgProperties[3].colid = DB_NULLID;  
  
    /*  
    Now that the properties are set, construct the DBPROPSET   
    structure (rgInitPropSet).  The DBPROPSET structure is used   
    to pass an array of DBPROP structures (InitProperties) to the   
    SetProperties method.  
    */  
    rgPropSets[0].guidPropertySet   = DBPROPSET_DBINIT;  
    rgPropSets[0].cProperties       = cProperties;  
    rgPropSets[0].rgProperties      = rgProperties;  
  
    // Get the IDBInitialize interface.  
    hr = CoCreateInstance(CLSID_SQLNCLI10,   
                            NULL,   
                            CLSCTX_INPROC_SERVER,  
                            IID_IDBInitialize,   
                            (void**)&pIDBInitialize);  
    if(FAILED(hr))  
    {  
        cout << "Failed to get IDBInitialize interface.\n";  
        // Release any references and return.  
        goto Exit;  
  
    } //end if  
  
    // Set initialization properties.  
    hr = pIDBInitialize->QueryInterface(IID_IDBProperties,  
                                        (void **)&pIDBProperties);  
    if(FAILED(hr))  
    {  
        cout << "Failed to get IDBProperties interface.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
    hr = pIDBProperties->SetProperties(cPropSets, rgPropSets);  
     if(FAILED(hr))  
    {  
        cout << "Failed to set properties for DBPROPSET_DBINIT.\n";  
        // Release any references and return.  
        goto Exit;  
    } //end if  
  
     hr = pIDBInitialize->Initialize();  
      if(FAILED(hr))  
    {  
        cout << "Failed to initialize.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
    //Create a session object.  
      hr = pIDBInitialize->QueryInterface(  
                                IID_IDBCreateSession,  
                                (void **)&pIDBCreateSession);  
       if(FAILED(hr))  
    {  
        cout << "Failed to get pIDBCreateSession interface.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
       hr = pIDBCreateSession->CreateSession(  
                                    NULL,   
                                    IID_IDBCreateCommand,  
                                    (IUnknown**)&pIDBCreateCommand);  
     if(FAILED(hr))  
    {  
        cout << "Failed to create session object.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
     // Get the CommandText object.  
     hr = pIDBCreateCommand->CreateCommand(  
                                    NULL,   
                                    riid,   
                                    (IUnknown**)ppIUnknown);  
     if(FAILED(hr))  
    {  
        cout << "Failed to create CommandText object.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
     return hr;  
Exit:  
    // Free up all allocated memory and release interface pointers.  
     return hr;  
  
} //end function  
//...............................................................  
HRESULT CreateTable(ICommandText* pICommandText)  
{  
    HRESULT hr = S_OK;  
  
    // Drop the xisting table.  
    hr = pICommandText->SetCommandText(  
                            DBGUID_DBSQL,  
                            L"DROP TABLE TestISeqStream");  
    if(FAILED(hr))  
    {  
        cout << "Failed to set command text DROP TABLE.\n";  
        // Release any references and return.  
        goto Exit;  
  
    } //end if  
  
    hr = pICommandText->Execute(NULL, IID_NULL, NULL, NULL, NULL);  
    if(FAILED(hr))  
    {  
        cout << "Failed to drop the table.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
    // Create a new table.  
    hr = pICommandText->SetCommandText(DBGUID_DBSQL,  
         L"CREATE TABLE TestISeqStream (col1 int,col2 image)");  
    if(FAILED(hr))  
    {  
        cout << "Failed to set command text CREATE TABLE.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
    hr = pICommandText->Execute(NULL, IID_NULL, NULL, NULL, NULL);  
    if(FAILED(hr))  
    {  
        cout << "Failed to create new table.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
    // Insert one row into table.  
    hr = pICommandText->SetCommandText(DBGUID_DBSQL,  
    L"INSERT INTO TestISeqStream(col1,col2) VALUES (1,0xAAAAAAAAAAAAAAAAA)");  
    if(FAILED(hr))  
    {  
        cout << "Failed to set command text INSERT INTO.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
    hr = pICommandText->Execute(NULL, IID_NULL, NULL, NULL, NULL);  
    if(FAILED(hr))  
    {  
        cout << "Failed to insert record in the table.\n";  
        // Release any references and return.  
        goto Exit;  
    } // end if  
  
Exit:  
    // Free up all allocated memory and release interface pointers.  
     return hr;  
  
} //end function  

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BLOB 與 OLE 物件
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