FreeTDS Development Group

["ZIGLIO, Frediano, VF-IT" <Frediano.Ziglio AT vodafone.com>]

> 
> On Feb 18, 2004, at 2:51 PM, Jonathan Monroe wrote:
> 
> > I think I have found an issue with the way the SQL_C_BINARY 
> data type 
> > is handled in the ODBC code.
> [snip]
> 
> It just occurred to me that the patch I provided for 
> convert_tds2sql.c 
> only fixed the problem for varchar columns - other column types will 
> still have some sort of conversion performed.  The better way of 
> handling it is probably to treat SQL_C_BINARY as a special 
> case and not 
> call tds_convert() at all.
> 
> So, the new patch would look like this:
> 
> convert_tds2sql.c:  v1.37:
> 81,84c81,102
> <       nRetVal = tds_convert(context, srctype, src, srclen, 
> nDestSybType, &ores);
> <       if (nRetVal < 0)
> <               return nRetVal;
> <
> ---
>  >       if (desttype == SQL_C_BINARY)
>  >       {
>  >               /* just copy the raw bytes */
>  >               if (destlen > 0) {
>  >                       cplen = (destlen > srclen) ? srclen 
> : destlen;
>  >                       assert(cplen >= 0);
>  >                       /* do not NULL terminate binary buffer */
>  >                       memcpy(dest, src, cplen);
>  >                       ret = cplen;
>  >               } else {
>  >                       /* if destlen == 0 we return only length */
>  >                       if (destlen != 0)
>  >                               ret = TDS_FAIL;
>  >               }
>  >       }
>  >       else
>  >       {
>  >               nRetVal = tds_convert(context, srctype, src, srclen, 
> nDestSybType, &ores);
>  >               if (nRetVal < 0)
>  >                       return nRetVal;
>  >       }
>  >
> 236,250c254
> <               tdsdump_log(TDS_DBG_FUNC, "convert_tds2sql: 
> outputting 
> binary data destlen = %d \n", destlen);
> <
> <               ret = nRetVal;
> <               if (destlen > 0) {
> <                       cplen = (destlen > nRetVal) ? nRetVal 
> : destlen;
> <                       assert(cplen >= 0);
> <                       /* do not NULL terminate binary buffer */
> <                       memcpy(dest, ores.ib, cplen);
> <               } else {
> <                       /* if destlen == 0 we return only length */
> <                       if (destlen != 0)
> <                               ret = TDS_FAIL;
> <               }
> <
> <               free(ores.ib);
> ---
>  >               /* handled as special case above */
> 
> 
> Anybody see any problems with doing it this way?
> 
> Jonathan Monroe
> 

You spot a real problem. I don't know if is correct to handle varchar as
a binary string (ie: '012345') however I don't know the real behaviour
for other types. For instance how MS ODBC return a datetime?? Same
format of wire (as FreeTDS does now) or converting to TIMESTAMP before
?? Some tests are needed to handle this type...

freddy77