难道csdn没人懂在vc下的ado连接数据库，数据库中的varbinary类型数据的读与写吗？我都问了好几天了。

[huaguli]

有谁写过数据库中的二进制数据的读取与写入啊？sql语句该怎么写呢？？谢谢大家！

[Kudeet]

http://www.vckbase.com/document/viewdoc/?id=252

[goodboyws]

读，数据保存在m_lpData
vValue = m_pRecordset->Fields->GetItem(vSegIndex)->Value;
// 读取数据大小
nDataSize = m_pRecordset->GetFields()->GetItem(vSegIndex)->ActualSize;

nDataType = vValue.vt;

if (nDataType == (VT_ARRAY | VT_UI1))
{
m_lpData = new char[nDataSize];
memset(m_lpData, 0, nDataSize);
char* pBufTemp = NULL;
SafeArrayAccessData(vValue.parray, (void **)&pBufTemp);
for (int i = 0; i < nDataSize; i++)
*(((char*)m_lpData)+i) = *(pBufTemp+i);
SafeArrayUnaccessData (vValue.parray);
return TRUE;
}

[goodboyws]

写
_bstr_t bstrSegName = strSegName;
VARIANT varBLOB;
SAFEARRAY *psa;
SAFEARRAYBOUND rgsabound[1];

// 保存BLOB数据
if(nDataSize > 0)
{
rgsabound[0].lLbound = 0;
rgsabound[0].cElements = nDataSize;
psa = SafeArrayCreate(VT_UI1, 1, rgsabound);
for (long i = 0; i < (long)nDataSize; i++)
SafeArrayPutElement (psa, &i, pBuf+i);
varBLOB.vt = VT_ARRAY | VT_UI1;
varBLOB.parray = psa;
m_pRecordset->GetFields()->GetItem(bstrSegName)->AppendChunk(varBLOB);
}
m_pRecordset->Update();
return TRUE;