Thanks. Good that this is known issue, and would be worked upon in future.
I think I can live with fixing it with some trial and errors .
/ Lalit
________________________________
From: Mateusz Loskot <[email protected]>
To: Lalit Bhasin <[email protected]>; SOCI general discussion list
<[email protected]>
Sent: Tuesday, June 11, 2013 10:05 PM
Subject: Re: [soci-users] bad_cast error (oracle backend)
On 11 June 2013 08:57, Lalit Bhasin <[email protected]> wrote:
>
> Here is my test code to simulate the problem:
>
> *****************
> #include <soci/oracle/soci-oracle.h>
> #include<soci/soci.h>
> #include<iostream>
>
> main()
>
> {
> soci::session sql( soci::oracle, "service=XE user=scott password=tiger"
> );
> soci::rowset<soci::row> rs = (
> sql.prepare << "select data_length+0, data_length from "
> << " user_tab_cols where table_name = 'TABLE2' ");
>
> soci::rowset<soci::row>::const_iterator it = rs.begin();
> soci::row const & row = *it;
> std::cout << "DATA_LENGTH + 0 = " << row.get<int>(0) <<std::endl;
> // no error here as expected
> std::cout << "DATA_LENGTH = " << row.get<int>(1) <<std::endl;
> // this gives bad_cast error. Why ??
>
> }
> *************************
I'm afraid you've hit the known nasty deficiency in SOCI integer types:
https://github.com/SOCI/soci/issues/90
> Now when running this executable:
>
> sqlplus> create table table2 ( a number);
> sqlplus> exit
>
> [ubuntu_host]$ ./a.out
> DATA_LENGTH + 0 = 22
> terminate called after throwing an instance of 'std::bad_cast'
> what(): St8bad_cast
> Aborted
> [ubuntu_host]$
>
>
> Any idea why I am getting bad_cast error on accessing data_length column
> from user_tab_cols view, even though the column is of type number ? The only
> way to access this column is using data_length+0 in select query.
I presume, one type is signed the other unsigned, and that hits the wall
of quite unfortunately simplified integral conversions in SOCI, currently.
I'm slowly working (investigating) on getting it right
(https://github.com/SOCI/soci/wiki/RFC1), but I'm too much
multitasking and dealing with unexpected bugfix releases in
meantime.
The only solution I can suggest is to match the right type by some
trial and error.
I know, I'm sorry :(
Best regards,
--
Mateusz Loskot, http://mateusz.loskot.net------------------------------------------------------------------------------
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