대규모 데이터 설정
SQL Server Native Client OLE DB 공급자를 사용하면 포인터를 소비자 저장소 개체에 전달하여 BLOB 데이터를 설정할 수 있습니다.
소비자는 이 데이터가 포함된 저장소 개체를 만들고 이 저장소 개체에 대한 포인터를 공급자에게 전달합니다. 그러면 공급자는 소비자 저장소 개체에서 데이터를 읽고 이를 BLOB 열에 씁니다.
자체의 저장소 개체에 대한 포인터를 전달하기 위해 소비자는 BLOB 열의 값을 바인딩하는 접근자를 만든 다음 이 접근자와 함께 IRowsetChange::SetData 또는 IRowsetChange::InsertRow 메서드를 호출합니다. 그러면 소비자의 저장소 개체에 저장소 인터페이스에 대한 포인터가 전달됩니다.
이 항목에서는 다음 함수와 함께 사용할 수 있는 기능에 대해 설명합니다.
IRowset:SetData
ICommand::Execute
IRowsetUpdate::Update
대규모 데이터를 설정하는 방법
자체의 저장소 개체에 대한 포인터를 전달하기 위해 소비자는 BLOB 열의 값을 바인딩하는 접근자를 만든 다음 IRowsetChange::SetData 또는 IRowsetChange::InsertRow 메서드를 호출합니다. BLOB 데이터를 설정하려면 다음과 같이 하십시오.
BLOB 열에 액세스하는 방법을 설명하는 DBOBJECT 구조를 만듭니다. DBOBJECT 구조의 dwFlag 요소를 STGM_READ로 설정하고 iid 요소를 ISequentialStream(표시할 인터페이스)으로 설정합니다.
행 집합 업데이트가 가능하도록 DBPROPSET_ROWSET 속성 그룹의 속성을 설정합니다.
DBBINDING 구조의 배열을 사용하여 각 열에 대해 하나씩 바인딩 집합을 만듭니다. DBBINDING 구조의 wType 요소를 DBTYPE_IUNKNOWN으로 설정하고 pObject 요소를 앞에서 만든 DBOBJECT 구조를 가리키도록 설정합니다.
구조의 DBBINDINGS 배열에 있는 바인딩 정보를 사용하여 접근자를 만듭니다.
GetNextRows를 호출하여 다음 행을 행 집합으로 인출합니다. GetData를 호출하여 행 집합에서 데이터를 읽습니다.
데이터 및 길이 표시기가 포함된 저장소 개체를 만든 다음 해당 BLOB 열을 바인딩하는 접근자와 함께 IRowsetChange::SetData(또는 IRowsetChange::InsertRow)를 호출하여 데이터를 설정합니다.
예
이 예에서는 BLOB 데이터를 설정하는 방법을 보여 줍니다. 이 예에서는 데이터를 만들어 예제 레코드를 추가하고 행 집합에서 해당 레코드를 인출한 다음 BLOB 필드의 값을 설정합니다.
#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