c++写入oracle数据库blob字段,读取blob到本地文件

void DlgImpRoadSection::OnOkBtnClicked()
{
#pragma region 验证

CString tempStr;

CString fileName;
m_FilePath.GetWindowText(fileName);
if (access((const char*)_bstr_t(fileName), 0) != 0)
{
ads_alert(L"文件不存在！");
return;
}

...

#pragma endregion

#pragma region 以二进制形式读文件。存入varBlob

CFile file;
if (file.Open(fileName, CFile::modeRead|CFile::typeBinary) == FALSE)
{
return;
}

long fileLen = file.GetLength(); // 文件长度

// 存放文件二进制流的指针
byte *fileBuffer = new byte[fileLen + 1];
file.Read(fileBuffer, fileLen);
file.Close();

// 指定一个一维安全数组（safe array）的边界
SAFEARRAYBOUND rgsabound[1];
rgsabound[0].lLbound = 0;
rgsabound[0].cElements = fileLen;

// 安全数组
SAFEARRAY *safeArray;
safeArray = SafeArrayCreate(VT_UI1, 1, rgsabound);

for (long i = 0; i < fileLen; i++)
{
SafeArrayPutElement (safeArray, &i, fileBuffer++);
}

// 存入数据库中的BLOB的类型数据。设置为BYTE类型的数组
VARIANT varBLOB;
varBLOB.vt = VT_ARRAY | VT_UI1;
varBLOB.parray = safeArray;

#pragma endregion

#pragma region 插入记录

CString sql = L"select * from TABLE_NAME where 1 = 0";

_RecordsetPtr rs;
rs.CreateInstance(__uuidof(Recordset));

try
{
if (rs->Open(sql.GetBuffer(0), g_conn.GetInterfacePtr(),
adOpenDynamic, adLockOptimistic, adCmdText) == S_FALSE)
{
return;
}

GUID guid;
CoCreateGuid(&guid);
CString id;
id.Format(L"%08X%04X%04X%02X%02X%02X%02X%02X%02X%02X%02X",
guid.Data1, guid.Data2, guid.Data3,
guid.Data4[0], guid.Data4[1], guid.Data4[2], guid.Data4[3],
guid.Data4[4], guid.Data4[5], guid.Data4[6], guid.Data4[7]);

rs->AddNew();

rs->PutCollect("ID", _variant_t(id));
rs->PutCollect("...", ...);

rs->PutCollect("CAD_FILE", _variant_t(""));
rs->GetFields()->GetItem("FILE")->AppendChunk(varBLOB);

if (rs->Update() == S_OK)
{
...
}
else
{
...
}
}
catch(...)
{
...
}

rs = NULL;

#pragma endregion

CDialog::OnOK();
}

#pragma region 从数据库读取文件存到本地

CString tempFile; // 要存储到本地文件名。
_RecordsetPtr rs;
rs.CreateInstance(__uuidof(Recordset));

CString sql;
sql.Format(L"select FILE from tablename where id = '%s'", id);

try
{
if (rs->Open(sql.GetBuffer(0), g_conn.GetInterfacePtr(),
adOpenDynamic, adLockOptimistic, adCmdText) == S_FALSE)
{
return false;
}

if (rs->adoEOF)
{
return false;
}

long dataSize = rs->GetFields()->GetItem("FILE")->ActualSize;

if (dataSize < 0)
{
return false;
}

_variant_t varBlob = rs->GetFields()->GetItem("FILE")->GetChunk(dataSize);;

if(varBlob.vt == (VT_ARRAY | VT_UI1)) //判断数据类型是否正确
{
char *pBuf = NULL;
SafeArrayAccessData(varBlob.parray, (void **)&pBuf); //得到指向数据的指针

CFile cadFile;

tempFile = appPath + "\\temp.dwg";;

if (cadFile.Open(tempFile,
CFile::modeCreate|CFile::modeWrite|CFile::typeBinary) == FALSE)
{
return false;
}

cadFile.Write(pBuf, dataSize);
cadFile.Close();

SafeArrayUnaccessData (varBlob.parray);
}
}
catch (...)
{
return false;
}

#pragma endregion