I have an UPDATE query that is always setting 0 records. When I cut and
paste the SQL into Access and use it, it fails in the same way unless I
coerce the date fields to be '=now()', in which case it works. I never get
errors, and if I don't try to update the date fields, I always update the
expected number of rows (1). When I do date conversion using the same
conversion function, then call CRowset::Add() to add a record to the same
table, it works as expected.
I am using OLEDB/C++ against Jet 4.0.
Here are some code fragments for reading enjoyment.
Any insights appreciated.
RDeW
---------------------------------
//accessor
class CFileUpdateByNameAccessor
{
public:
void ClearRecord()
{
memset(&this->m_DriveName, 0, offsetof(CFileUpdateByNameAccessor,
m_TextType) + sizeof(m_TextType));
}
wchar_t m_DriveName[DRIVEBUFSIZE];
wchar_t m_DirName[DIRECTORYBUFSIZE];
wchar_t m_FileName[FILEBUFSIZE];
LONG m_Checksum;
LONG m_SizeLo32;
DATE m_CreationDateTime;
DATE m_LastAccessDateTime;
DATE m_ModificationDateTime;
DATE m_SSLastUpdate;
LONG m_TextType;
BEGIN_PARAM_MAP(CFileUpdateByNameAccessor)
COLUMN_ENTRY_TYPE(1, DBTYPE_DATE, m_CreationDateTime)
COLUMN_ENTRY_TYPE(2, DBTYPE_DATE, m_ModificationDateTime)
COLUMN_ENTRY_TYPE(3, DBTYPE_DATE, m_LastAccessDateTime)
COLUMN_ENTRY_TYPE(4, DBTYPE_DATE, m_SSLastUpdate)
COLUMN_ENTRY(5, m_Checksum)
COLUMN_ENTRY(6, m_SizeLo32)
COLUMN_ENTRY(7, m_TextType)
COLUMN_ENTRY(8, m_DriveName)
COLUMN_ENTRY(9, m_DirName)
COLUMN_ENTRY(10, m_FileName)
END_PARAM_MAP()
DEFINE_COMMAND_EX(CFileUpdateByNameAccessor, L"\
UPDATE Files \
SET \
CreationDateTime = (?), \
ModificationDateTime = (?), \
LastAccessDateTime = (?), \
SSLastUpdate = (?), \
Checksum = (?), \
SizeLo32 = (?), \
TextType = (?) \
WHERE \
Files.FileID in \
(SELECT Files.FileID from files, directories, drives \
where drives.name = (?) and \
directories.name = (?) and \
files.name = (?) and \
drives.driveid = directories.driveid and \
files.directoryid = directories.directoryid)")
};
///date conversion function, uses IDataConvert, returns S_OK and
reasonable-looking values
bool CMyDB::FileTimeToDBDate(const FILETIME *pFT, DATE *pD)
{
unsigned long nBytesConverted = 0;
DBSTATUS dbStatus = {0,};
assert(pFT);
assert(pD);
assert(_Module.pCvt);
/*
HRESULT DataConvert (
DBTYPE wSrcType,
DBTYPE wDstType,
ULONG cbSrcLength,
ULONG * pcbDstLength,
void * pSrc,
void * pDst,
ULONG cbDstMaxLength,
DBSTATUS dbsSrcStatus,
DBSTATUS * pdbsStatus,
BYTE bPrecision,
BYTE bScale,
DBDATACONVERT dwFlags);
*/
HRESULT hr =
_Module.pCvt->DataConvert(
DBTYPE_FILETIME, //file time goes in
DBTYPE_DATE, //date comes out
sizeof(*pFT), //size of input
&nBytesConverted, //how many bytes did we get?
(void *)pFT, //data in
(void *)pD, //data out
sizeof(*pD), //size of data out
DBSTATUS_S_OK, //magic per Status page in OLEDB docs
&dbStatus, //address to store status out
0, //don't care about precision ...
0, //...or about scale
DBDATACONVERT_DEFAULT //default conversion
);
if(FAILED(hr))
{
LogDBError(__WFILE__, __LINE__, hr);
return false;
}
assert(nBytesConverted);
assert(SUCCEEDED(dbStatus));
return true;
}
//------------------------UPDATE code, szFN has a "nice" file name here ...
wcsncpy(fun.m_DriveName, szFN, (pDir - szFN));
wcsncpy(fun.m_DirName, pDir, (pFile - pDir));
wcsncpy(fun.m_FileName, pFile, wcslen(pFile));
//here we get the file dates and times as FILETIME structs
if(!GetFileAttributesExW(szFN, GetFileExInfoStandard, &gfi))
return E_INVALIDARG;
FILETIME ft = {0,};
SYSTEMTIME st = {0,};
GetSystemTime(&st);
SystemTimeToFileTime(&st, &ft);
//convert the FILETIMEs to db DATE per fxn above
FileTimeToDBDate(&ft, &fun.m_SSLastUpdate);
FileTimeToDBDate(&gfi.ftCreationTime, &fun.m_CreationDateTime);
FileTimeToDBDate(&gfi.ftLastAccessTime, &fun.m_LastAccessDateTime);
FileTimeToDBDate(&gfi.ftLastWriteTime, &fun.m_ModificationDateTime);
fun.m_Checksum = CalcChecksum(szFN);
fun.m_SizeLo32 = gfi.nFileSizeLow;
hr = fun.Open();
//...error trap omitted, always get S_OK, but nothing updated, stepping into
code shows 0 records updated.
fun.Close(); 1 3572
Sorry, that is CRowset::Insert(), not Add()
RDeW
"Riley DeWiley" <ri***********@gmail.com> wrote in message
news:Wf********************@seanet.com... I have an UPDATE query that is always setting 0 records. When I cut and paste the SQL into Access and use it, it fails in the same way unless I coerce the date fields to be '=now()', in which case it works. I never get errors, and if I don't try to update the date fields, I always update the expected number of rows (1). When I do date conversion using the same conversion function, then call CRowset::Add() to add a record to the same table, it works as expected.
I am using OLEDB/C++ against Jet 4.0.
Here are some code fragments for reading enjoyment.
Any insights appreciated.
RDeW
--------------------------------- //accessor class CFileUpdateByNameAccessor
{
public:
void ClearRecord()
{
memset(&this->m_DriveName, 0, offsetof(CFileUpdateByNameAccessor, m_TextType) + sizeof(m_TextType));
}
wchar_t m_DriveName[DRIVEBUFSIZE];
wchar_t m_DirName[DIRECTORYBUFSIZE];
wchar_t m_FileName[FILEBUFSIZE];
LONG m_Checksum;
LONG m_SizeLo32;
DATE m_CreationDateTime;
DATE m_LastAccessDateTime;
DATE m_ModificationDateTime;
DATE m_SSLastUpdate;
LONG m_TextType; BEGIN_PARAM_MAP(CFileUpdateByNameAccessor)
COLUMN_ENTRY_TYPE(1, DBTYPE_DATE, m_CreationDateTime)
COLUMN_ENTRY_TYPE(2, DBTYPE_DATE, m_ModificationDateTime)
COLUMN_ENTRY_TYPE(3, DBTYPE_DATE, m_LastAccessDateTime)
COLUMN_ENTRY_TYPE(4, DBTYPE_DATE, m_SSLastUpdate)
COLUMN_ENTRY(5, m_Checksum)
COLUMN_ENTRY(6, m_SizeLo32)
COLUMN_ENTRY(7, m_TextType)
COLUMN_ENTRY(8, m_DriveName)
COLUMN_ENTRY(9, m_DirName)
COLUMN_ENTRY(10, m_FileName)
END_PARAM_MAP()
DEFINE_COMMAND_EX(CFileUpdateByNameAccessor, L"\
UPDATE Files \
SET \
CreationDateTime = (?), \
ModificationDateTime = (?), \
LastAccessDateTime = (?), \
SSLastUpdate = (?), \
Checksum = (?), \
SizeLo32 = (?), \
TextType = (?) \
WHERE \
Files.FileID in \
(SELECT Files.FileID from files, directories, drives \
where drives.name = (?) and \
directories.name = (?) and \
files.name = (?) and \
drives.driveid = directories.driveid and \
files.directoryid = directories.directoryid)")
}; ///date conversion function, uses IDataConvert, returns S_OK and reasonable-looking values
bool CMyDB::FileTimeToDBDate(const FILETIME *pFT, DATE *pD)
{
unsigned long nBytesConverted = 0;
DBSTATUS dbStatus = {0,};
assert(pFT);
assert(pD);
assert(_Module.pCvt);
/*
HRESULT DataConvert (
DBTYPE wSrcType,
DBTYPE wDstType,
ULONG cbSrcLength,
ULONG * pcbDstLength,
void * pSrc,
void * pDst,
ULONG cbDstMaxLength,
DBSTATUS dbsSrcStatus,
DBSTATUS * pdbsStatus,
BYTE bPrecision,
BYTE bScale,
DBDATACONVERT dwFlags);
*/
HRESULT hr =
_Module.pCvt->DataConvert(
DBTYPE_FILETIME, //file time goes in
DBTYPE_DATE, //date comes out
sizeof(*pFT), //size of input
&nBytesConverted, //how many bytes did we get?
(void *)pFT, //data in
(void *)pD, //data out
sizeof(*pD), //size of data out
DBSTATUS_S_OK, //magic per Status page in OLEDB docs
&dbStatus, //address to store status out
0, //don't care about precision ...
0, //...or about scale
DBDATACONVERT_DEFAULT //default conversion
);
if(FAILED(hr))
{
LogDBError(__WFILE__, __LINE__, hr);
return false;
}
assert(nBytesConverted);
assert(SUCCEEDED(dbStatus));
return true;
} //------------------------UPDATE code, szFN has a "nice" file name here ...
wcsncpy(fun.m_DriveName, szFN, (pDir - szFN));
wcsncpy(fun.m_DirName, pDir, (pFile - pDir));
wcsncpy(fun.m_FileName, pFile, wcslen(pFile));
//here we get the file dates and times as FILETIME structs
if(!GetFileAttributesExW(szFN, GetFileExInfoStandard, &gfi))
return E_INVALIDARG;
FILETIME ft = {0,};
SYSTEMTIME st = {0,};
GetSystemTime(&st);
SystemTimeToFileTime(&st, &ft);
//convert the FILETIMEs to db DATE per fxn above
FileTimeToDBDate(&ft, &fun.m_SSLastUpdate);
FileTimeToDBDate(&gfi.ftCreationTime, &fun.m_CreationDateTime);
FileTimeToDBDate(&gfi.ftLastAccessTime, &fun.m_LastAccessDateTime);
FileTimeToDBDate(&gfi.ftLastWriteTime, &fun.m_ModificationDateTime); fun.m_Checksum = CalcChecksum(szFN);
fun.m_SizeLo32 = gfi.nFileSizeLow;
hr = fun.Open();
//...error trap omitted, always get S_OK, but nothing updated, stepping into code shows 0 records updated.
fun.Close();
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