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

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--- Carl McClellan <[email protected]> wrote:
> 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)
>
>
>


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