Büyük veri ayarlama
İle SQL Server yerel istemci ole db sağlayıcı yapabilirsiniz küme suretiyle bir işaretçi bir tüketici depolama nesnesi. için blob veri
Tüketici bu sağlayıcı için depolama nesnesi gösteren bir işaretçi geçirir ve verileri içeren bir depolama nesnesi oluşturur.Sağlayıcı veri tüketici depolama nesneden okur ve blob sütun yazar.
Kendi depolama nesnesi için bir işaretçi geçirmek için tüketici oluşturur bir erişimci , değer blob sütun bağlar.Daha sonra tüketici çağırır IRowsetChange::SetData veya IRowsetChange::InsertRow yöntem ile erişimci , blob sütun bağlar.İşaretçi bir depolama arabirim tüketici depolama nesne üzerinde geçirmeden.
Bu konu aşağıdaki işlevleri ile kullanılabilen işlevselliği başvurur:
IRowset:SetData
ICommand::Execute
IRowsetUpdate::Update
Büyük veri ayarlama hakkında
Tüketici, kendi depolama nesnesi için bir işaretçi geçirmek için DAMLA değerini bağlayan bir erişimci oluşturur sütun sonra çağırır IRowsetChange::SetData veya IRowsetChange::InsertRow yöntemleri.İçin küme blob verileri:
blob sütun nasıl erişileceğini açıklayan bir dbobject yapısı oluşturun.küme dwFlag stgm_read ve küme dbobject yapısı öğesi iid IID_ISequentialStream (gösterilmesine izin arabirim) öğesine.
Satır kümesi güncelleştirilebilir, bu nedenle dbpropset_rowset özellik grubu özelliklerini ayarlayın.
Oluşturma bir küme , DBBINDING yapıları dizisi kullanarak bağları (bir, her sütunun).Set wType DBBINDING yapısına DBTYPE_IUNKNOWN, öğe ve pObject öğesi oluşturduğunuz dbobject yapısı işaret edecek.
Oluşturma bir erişimci bağlama bilgi yapıları dizisi DBBINDINGS kullanarak.
Call GetNextRows sonraki satır satır kümesi getirmek için.Call GetData satır kümesi ' verileri okunamıyor.
Verileri (ve ayrıca uzunluğu göstergesi) içeren bir depolama nesnesi oluşturun ve sonra call IRowsetChange::SetData (veya IRowsetChange::InsertRow) ile erişimci veri küme için blob sütun bağlar.
Örnek
Bu örnek gösterir nasıl küme blob verileri.Örnek bir tablo oluşturur örnek kaydı ekler Satır kümesi bu kayıtta getirir ve ardından DAMLA alan değerini ayarlar:
#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