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

MessageSorry, I am a consumer template guy.

This may not be of much help to you, but if someone has a similar desire and is using the
consumer templates, then in the consumer templates, I would have solved the problem like so.

class CSomeAccessor {
    LONG m_Val;
    BEGIN_ACCESSOR(CSomeAccessor)
        COLUMN_ENTRY(1, m_Val)
    END_ACCESSOR( )
};

CCommand<CAccessor<CSomeAccessor> > Cmd;

CSomeAccessor AccArray[10];

// Loop
Cmd.MoveNext( );
memcpy( AccArray[n], Cmd.GetBuffer( ), sizeof(CSomeAccessor));
// Do Something
// Term Loop



  ----- Original Message ----- 
  From: Carl McClellan 
  To: [email protected] 
  Sent: Wednesday, April 24, 2002 12:58 PM
  Subject: Re: [OLEDB_DEV] 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 
      To: [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 
      Velocitor Solutions 
      704-731-5396(P) 
      704-527-1234(F) 
      770-633-7427(M)