Re: How do I get data from buffer after call to IRows et GetData?

Huh? Robert, are you referring to consumer template classes? Im using raw
OLE DB. IAccessor interface does not support those methods. Anyways, I could
have multiple accessors and I could supply the same memory buffer
(potentially) to copy the data from the accessor to the buffer. Memory is
client-owned in my example (sorry, I should have made that clear)


-----Original Message-----
From: Robert Sedor [mailto:[email protected]]
Sent: Wednesday, April 24, 2002 11:56 AM
To: [email protected]
Subject: Re: [OLEDB_DEV] How do I get data from buffer after call to IRowset
GetData?



Your Accessor is your buffer.

ex.
pRowset->GetData( hRow, pAccessor->GetHAccessor(nAccessor),
pAccessor->GetBuffer( ) );

Robert Sedor
Pitney Bowes, Inc.


----- Original Message -----
From: Carl McClellan <mailto:[email protected]>
To: [email protected] <mailto:[email protected]>
Sent: Wednesday, April 24, 2002 11:23 AM
Subject: [OLEDB_DEV] How do I get data from buffer after call to IRowset
GetData?


Hi everybody,

I have a couple of questions about getting data out of a buffer after
calling IRowset GetData.
I have allocated a BYTE array with the appropriate number of bytes based on
the max row size....

BYTE* pBuffer = (BYTE*)malloc(dwOffset);

After the call to GetData I am ready to get the data for each column...


hr = pIRowset->GetData(rghRows[0],hAccessor,pBuffer);

for (ULONG ulCurrentCol = 0; ulCurrentCol < lNumCols; ulCurrentCol++)
{

        .... Get column data

}



The problem I am having is accessing certain types of data from the buffer.
If pBindings is my array of DBBINDING structures, then I access the data
THUSLY

pBuffer[pBindings[ulCurrentCol].obValue]


Now, I assume that obValue is a 32 bit value that holds a pointer to the
real data so in
Order to access the data, I need to dereference the pointer and cast the
BYTE away to whatever....

LONG *pLongValue =
reinterpret_cast<LONG*>(&pBuffer[pBindings[ulCurrentCol].obValue]);

DOUBLE *pDoubleValue =
reinterpret_cast<DOUBLE*>(&pBuffer[pBindings[ulCurrentCol].obValue]);

LPWSTR pwszString = (LPWSTR)&pBuffer[pBindings[ulCurrentCol].obValue];

And so on and so forth....


The problem is that I can never seem to get any meaningfull  data out of
columns that return
Doubles, currency, or dbtimestamp values. Having said that, I know that the
status is DBSTATUS_S_OK
(because I am binding VALUE | LENGTH | STATUS when I bind the columns).


The platform I am using is SQL Server CE (this is a program I am writing on
a Pocket PC device).


I would LOVE to see some sample code that somebody has written that extracts
data and tests the status
Of any coulumn/type.

I hope this was clear....

Carl McClellan
Software Engineer
 <http://www.velocitorsolutions.com> Velocitor Solutions
704-731-5396(P)
704-527-1234(F)
770-633-7427(M)