[Python-sybase-misc] Passing SQL NULL to a stored procedure - throws an exception

[Jeffrey Z. <Jef...@q-...>]

Hi,

 

I need to pass SQL NULL for one of the input parameters to a stored
procedure.  This stored procedure is called via the usual:

 

    cursor.callproc('storedprocname', parameterdictionary)

 

The usual way to pass SQL NULL using the Python DB-API is to pass None
instead.  However, this causes python-sybase to throw an exception, as
shown here:

 

    Traceback (most recent call last):

      File
"/home/jeffreyz/workspace-3.5/generate-client-test-data/src/generate_dat
a_tests.py", line 100, in <module>

        '@op_ClientNumber': Sybase.OUTPUT(1)})

      File "build/bdist.linux-i686/egg/Sybase.py", line 426, in callproc

      File "build/bdist.linux-i686/egg/Sybase.py", line 703, in _start

      File "build/bdist.linux-i686/egg/Sybase.py", line 717, in
_mainloop

      File "build/bdist.linux-i686/egg/Sybase.py", line 761, in
_raise_error

    Sybase.DatabaseError: Msg 257, Level 16, State 1, Procedure
qp_GUI_ClientInsert

    Implicit conversion from datatype 'INT' to 'UNIVARCHAR' is not
allowed.  Use the CONVERT function to run this query.

 

For some reason, it triggers an "Implicit conversion from datatype 'INT'
to 'UNIVARCHAR' is not allowed" exception.  For this particular case,
the input parameter is of type UNIVARCHAR, but this problem is not
particular to input parameters of only this type.  For this particular
case, SQL NULL is a legal value to pass to the stored procedure.

 

I have found one other reference to this issue here:

 

 
http://www.archivum.info/comp.databases.sybase/2007-08/00008/15.0.2_upgr
ade_issue_wrt_passing_null_parameters_to_procedure

 

Is this a known problem?  Is there a simple fix?  Or am I doing
something stupid?

 

Regards,

Jeffrey