Re: Empty string in db-lib

"[email protected]" <[email protected]> Mon, 10 May 2010 09:22:10 +0200

Newsgroups	gmane.comp.db.tds.freetds
Message-ID	<[email protected]>

hi,

>>> Is it possible to send an empty string as a parameter when making rpc
>>> calls? All my efforts so far seem to result in the parameter ending up
>>> being NULL when doing a trace on the server!
>>
>> It works.  Cf. src/dblib/unittests/rpc.c.

>> According to Sybase, "If the value of the RPC parameter is NULL, pass
>> datalen as 0, even if type is a fixed-length datatype."  That's what the
>> unit test does, and the server recognizes them as NULL.

> >From that it looks like it isn't possible to just send an empty string
> '' which of course is different to NULL? Is this a limitation of
> db-lib or the TDS protocol?

We had the same issue with CTLib.
Search mailing-list archive for "FreeTDS always setting empty
VARCHAR's to NULL" (24 May 2009).

A similar fix might be required for dblib.


Regards,
  Andrew Victor