FreeTDS Development Group

[Sebastien FLAESCH <sf AT 4js.com>]

Hi Frediano,

First, thanks a lot for looking at this cursor issue!

ZIGLIO, Frediano, VF-IT wrote:
> I think I have to check how attributes change in MS ODBC... perhaps
> setting SENSITIVITY change also CURSOR_TYPE ??

As I wrote in a previous mail, you should test all possible combinations
of SQL Statement handle attributes with the MS ODBC MDAC dribver, and see
in the SQL Server Profiler trace what sp_cursor* calls it generates.

Resource in SQL Server 2005 MSDN (you probably know about this link):

http://msdn2.microsoft.com/en-us/library/ms130794.aspx

...

We do use the following SQLSetStmtAttr() attributes:

For scrollable cursors:

    SQL_ATTR_CURSOR_SCROLLABLE, SQL_SCROLLABLE
    SQL_ATTR_CURSOR_SENSITIVITY, SQL_INSENSITIVE

For SELECT FOR UPDATE cursors (forward only):

    SQL_ATTR_CONCURRENCY, SQL_CONCUR_LOCK

For normal cursors, to get "Fast-forward cursors" (MSSQL specific attribute):

    SQL_SOPT_SS_CURSOR_OPTIONS, SQL_CO_FFO

In some situations, to force server to prepare (MSSQL specific attribute):

    SQL_SOPT_SS_DEFER_PREPARE, SQL_DP_OFF

We always set the cursor name with:

    SQLSetCursorName(...)  => that generates a sp_cursoroption call I believe.

We do also use array-fetch / column-wise binding (SQL_ATTR_ROW_BIND_TYPE,
SQL_BIND_BY_COLUMN) but that's probably another topic...

...

As a side note you may also install / test with SQL Server 2005 and the new
SQL Native Client driver...

Bye
Seb

ZIGLIO, Frediano, VF-IT wrote:
> > Dear all,
> > (hope it helps to send such little test programs in this 
> > mailing list).
> >
> > Attached a little test program executing 2 statements concurrently.
> >
> > For now with FreeTDS 0.65 I get:
> >
> > Error -1 at: SQLExecute 2
> > Diagnostic info:
> >    SQL State: 24000
> >    SQL code : 0
> >    Message  : [FreeTDS][SQL Server]Invalid cursor state
> >
> > When I run the same program with SQL Native Client, I get 
> > following output:
> >
> >  >> Fetch from 1: [aaa]
> >  >> Fetch from 2: [aaa]
> >
> > Note that you must set a statement attribute like:
> >
> > SQL_ATTR_CURSOR_SENSITIVITY, (SQLPOINTER) SQL_SENSITIVE
> >
> > or:
> >
> > SQL_ATTR_CONCURRENCY, (SQLPOINTER) SQL_CONCUR_LOCK
> >
> > ... to get sp_cursor* driven cursors, as you probably know.
> >
> > It's certainly a good idea to test all possible statement 
> > attributes you can
> > set with ODBC, and check what SQL Native Client sends to the server...
> >
> > There are a couple of sp_cursoroption calls you should take care of.
> >
> > Seb
>
> Well... 
> step 1. Add tests to out unittests... done, see
> http://freetds.cvs.sourceforge.net/freetds/freetds/src/odbc/unittests/?s
> ortby=date#dirlist
> step 2. Do tests work? No...
> step 2. See how tests works under Windows. I used MS ODBC (no Native)
> with mssql2k
>
> start test cursor3.exe  
> odbctest
> --------
>
> connection parameters:
> server:   'TESTSRV'
> user:     'test'
> password: '????'
> database: 'test'
> use test
> > > Fetch from 1: [aaa]
> > > Fetch from 2: [aaa]
> ok test cursor3.exe 
> start test cursor4.exe  
> odbctest
> --------
>
> connection parameters:
> server:   'TESTSRV'
> user:     'test'
> password: '????'
> database: 'test'
> use test
> > > New value after update = [xxx] (should be [xxx]) 
> ok test cursor4.exe 
> start test cursor5.exe  
> odbctest
> --------
>
> connection parameters:
> server:   'TESTSRV'
> user:     'test'
> password: '????'
> database: 'test'
> use test
> > > fetch  3          0 : 3 [ccc                 ]
> > > fetch  4          0 : 2 [bbb                 ]
> > > fetch  4          0 : 1 [aaa                 ]
> > > fetch  4          0 : no data found
> > > fetch  1          0 : 1 [aaa                 ]
> > > fetch  1          0 : 2 [bbb                 ]
> > > fetch  1          0 : 3 [ccc                 ]
> > > fetch  1          0 : no data found
> > > fetch  2          0 : 1 [aaa                 ]
> > > fetch  1          0 : 2 [bbb                 ]
> > > fetch  1          0 : 3 [ccc                 ]
> > > fetch  5          3 : 3 [ccc                 ]
> > > fetch  6         -2 : 1 [aaa                 ]
> > > fetch  6         -2 : no data found
> > > fetch  6          5 : no data found
> ok test cursor5.exe 
>
> Now, why our tests fails... It seems that the combination you use to
> setup cursor is not accepted by out driver... problem 2 (problem 1 is
> prepared cursors).
>
> I think I have to check how attributes change in MS ODBC... perhaps
> setting SENSITIVITY change also CURSOR_TYPE ??
>
> freddy77
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