Re: Commit to odbc.c from 5/19/2010 breaks prepared statements with pyodbc

Well.. you will note the u before the string. For better consistency
now ODBC driver does not convert data to multi-byte and can return
wide encoding. Probably Ruby read wide encoding and wrongly assume
that unixODBC returns wchat_t encoding. This should cause the problem.
unixODBC usually (if not configured otherwise) use 2 bytes
(ucs2/utf16) for wide encoding.

Could you post tests sources?

freddy77

2010/10/18 Peter C. Norton <[email protected]>:
> Another regression, fix unknown so far.  Between the same two revisions, the following has broken.
>
> Before:
>
> nortonp@sys4 17:04 ~/work/odbc_tests $ ./test_mssql_select.py
> Testing sybase
> [('SYBQA1', )]
> Testing mssql
> [('DBDEVNYC2', )]
>
> After upgrading to 0.83.dev.20100902 or later:
>
> Testing sybase
> [('SYBQA1', )]
> Testing mssql
> [(u'DDVY', )]
>
> I haven't narrowed this down to a particular changeset yet.
>
> -Peter
>
>
> On Fri, Oct 15, 2010 at 01:58:45PM -0400, Peter C. Norton wrote:
>> Hi, I've got another bug report.  At my site we've run into a
>> regression when going from the following:
>>
>> pyodbc-2.1.7
>>  depends on
>> unixODBC-2.2.14
>>  which depends on
>> freetds-0.82.1.dev.20091223
>>
>> to the same pyodbc and unixODBC, but upgrading to
>> freetds-0.83.dev.20100902 + various patches from upstream.  When users
>> tested it I got the following succinct bug report:
>>
>> import pyodbc
>> def the_test(db_name):
>>     db = pyodbc.connect("DSN=%s;UID=<USERNAME>;PWD=<PASSWORD>;DATABASE=<any database>;APP=python_test" % db_name)
>>     q = db.execute("select * from <any table> where type = ?", (1,))
>>     print q.fetchall()
>>
>> the_test("SYBASE")
>>
>> results in the following error:
>>
>> Error: ('HY000', 'The driver did not supply an error!')
>>
>> Confirmed on solaris x86 and linux/64-bit.  I've bisected the changes
>> made back to 5/19/2010 via the freetds git repository and I found that
>> the following broke prepared statements from pyodbc:
>>
>> http://github.com/brianb/FreeTDS/commit/2ed78ea4dd9018927b56822e318e0b5ac9401b98#diff-2
>>
>> Specifically the chunk between line 1301 and 1313. The relevent chunk of code is this:
>>
>>               if (desc->type == DESC_IRD && ((TDS_STMT*)desc->parent)->need_reprepare && \
>>                   odbc_update_ird((TDS_STMT*)desc->parent, errs) != SQL_SUCCESS) \
>>                       exit; \
>>
>> Reverting the patch to the pre-2010-05-19 state has the preprocessor
>> replace the above with:
>>
>> #define IRD_UPDATE(desc, errs, exit) do { } while(0)
>>
>> which may just be masking an error, but I do not know.  Backing this
>> out causes prepared statements to work again.  Are there any gotchas
>> to reverting this change?  And is there a better/more correct fix for
>> this?
>>
>> By the way, this works fine when I point the same test an an MSSQL 2005 or 2008 server.
>>
>> Thanks,
>>
>> -Peter
>>
>>
>>
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