FreeTDS Development Group

[Зверев Виталий Борисович <VZverev AT genesis.spb.ru>]

Hello James, Frediano.
I'm still digging of placeholder's parser and begin thinking about 
correlations with Pandor's box. Maybe you kindly prompt me how to solve one 
puzzle:
There is next T-SQL batch:

select count(1) as cnt ,type into #temp1 from sysobjects group by type ; 
select cnt,type from #temp1 where cnt > ?

How to get datatype of placeholder (#temp1.cnt)? 
Obviously solution exists (like SQLDescribeParam)

SQLPrepare(hstmt, ( unsigned char * )"select count(1) as cnt ,type into 
#temp1 from sysobjects group by type ; select cnt,type from #temp1 where cnt 
> ? ", SQL_NTS);
SQLDescribeParam(hstmt,1, &DataType, &ParamSize, &DecimalDigits, &Nullable);

but...
The native MS odbc driver give me an answer ;) :
SET FMTONLY ON select  cnt from sysobjects where 1=2 SET FMTONLY OFF
Error :[Microsoft][ODBC SQL Server Driver][SQL Server]Invalid column name 
'cnt'.

Couldn't you check this behavior for another product combinations, say Merant 
ODBC across Shiloh, Yukon or ASE?

Sincerely yours. 
-------------------------------------------------------
Vitaly Zverev, OCP DBA 8&8i
Oracle E-Business Suite &
Infiniband Linux Cluster Administrator
Genesis Ltd., St.Petersburg, Russia

 

> -----Original Message-----
> From: freetds-bounces AT lists.ibiblio.org 
> [mailto:freetds-bounces AT lists.ibiblio.org] On Behalf Of James 
> K. Lowden
> Sent: Wednesday, November 16, 2005 7:29 AM
> To: FreeTDS Development Group
> Subject: Re: [freetds] parsing T-SQL with flex & yacc (was: 
> segfaultinPerl'sEmail::Store when using freetds)
> 
> ú×ÅÒÅ× ÷ÉÔÁÌÉÊ âÏÒÉÓÏ×ÉÞ wrote:
> > James, Frediano,
> > thanks for comments in friendly atmosphere (I'm not a 
> native English 
> > writer, so excuse me my ugly essay)
> 
> When I can apologize for my Russian, I'll pass judgement on 
> your English, Vitaly.  :-)
> 
> You're undertaking something ambitious and potentially very 
> useful.  Being friendly is pretty easy by comparison.  
> 
> I am hoping that you will write a function that will accept 
> an SQL string, find the placeholders, and return an array of 
> structures.  Each structure will contain:
> 
>       database
>       system object name
>       system object type (S/U/P/V/TR, per sysobjects)
>       column/parameter name
> 
> In this query, for example:
> 
>       select * from systypes where name = ?
> 
> The answer would be:
> 
>       database = NULL
>       object name = 'systypes'
>       object type = 'S'
>       column/parameter name = 'name'
>       
> The caller of your function will formulate a query for the 
> server about the datatype of each placeholder.  To do that it 
> may need  to know if the placeholder is a parameter to a 
> stored procedure or function, or will be compared to a 
> column.  Not everything can be found in syscolumns.  
> 
> > BTW, FireBird like a Sybase has open interface to 
> parametrised Dinamic 
> > SQL parser & ODBC driver (with SQLDescribeParam implementation) 
> > 
> http://cvs.sourceforge.net/viewcvs.py/*checkout*/firebird/fire
> bird2/src/dsql/parse.y?rev=1.193.
> > 
> 
> Yep.  Firebird has a very different design and SQL.  I know a 
> little about it.  I contributed patches that made sure it 
> runs on NetBSD.  
> 
> Regards, 
> 
> --jkl
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