Re: How to properly perform this?

Dave,

On Sat, Mar 7, 2026 at 5:14 PM Igor Korot <ikorot01(at)gmail(dot)com> wrote:
>
> Dave,
>
> This is from the gdb session:
>
> Hi, David,
>
> On Sat, Mar 7, 2026 at 1:06 PM Igor Korot <ikorot01(at)gmail(dot)com> wrote:
> >
> > Hi, Dave,
> > I think its just an empty column.
> >
> > Is there a way to treat it as NULL?
> >
> > P.S.: Sorry for top-posting.
> >
> > On Sat, Mar 7, 2026 at 5:41 AM Dave Cramer <davecramer(at)postgres(dot)rocks> wrote:
> > >
> > >
> > > Dave Cramer
> > > www.postgres.rocks
> > >
> > >
> > > On Sat, 7 Mar 2026 at 01:10, Igor Korot <ikorot01(at)gmail(dot)com> wrote:
> > >>
> > >> Hi, ALL,
> > >> I'm trying to execute following query:
> > >>
> > >> draft=# SELECT c.relname AS name, ixs.tablespace, ARRAY(SELECT
> > >> a.attname FROM pg_attribute a WHERE a.attrelid = idx.indrelid AND
> > >> a.attnum = ANY(idx.indkey) AND a.attnum > 0 ORDER BY
> > >> array_position(idx.indkey, a.attnum) OFFSET idx.indnkeyatts) AS
> > >> included, c.reloptions AS storage FROM pg_index idx, pg_class c,
> > >> pg_namespace n, pg_class t, pg_indexes ixs WHERE ixs.indexname =
> > >> c.relname AND c.oid = idx.indexrelid AND t.oid = idx.indrelid AND
> > >> n.oid = c.relnamespace AND idx.indisprimary AND n.nspname = 'public'
> > >> AND t.relname = 'leagues';
> > >> name | tablespace | included | storage
> > >> --------------+------------+----------+---------
> > >> leagues_pkey | | {} |
> > >> (1 row)
> > >>
> > >>
> > >> My code is as follows:
> > >>
> > >> while( ( ret = SQLGetData( m_hstmt, 4, SQL_C_WCHAR,
> > >> index_param.get(), 255, &ind[3] ) ) != SQL_NO_DATA )
> > >> {
> > >> if( ret == SQL_SUCCESS || ret == SQL_SUCCESS_WITH_INFO )
> > >> {
> > >> auto numBytes = ind[3];
> > >> if( ind[3] == SQL_NO_TOTAL )
> > >> numBytes = 255;
> > >> else if( ind[3] > 255 )
> > >> numBytes = 255;
> > >> str_to_uc_cpy( options, index_param.get() );
> > >> }
> > >> else
> > >> {
> > >> GetErrorMessage( errorMsg, STMT_ERROR );
> > >> result = 1;
> > >> }
> > >> }
> > >> Unfortunately it goes into the loop because apparently the driver or
> > >> the server keeps seeing the last column as having data and returns
> > >> SQL_SUCCESS.
> > >>
> > >> What is the proper way to resolve this?
> > >>
> > >> I'm using unixODBC with PostgreSQL 16.
> > >>
> > >> My odbc.ini looks like this:
> > >>
> > >> [code]
> > >> [postgres]
> > >> Driver=Postgres
> > >> Description=Postgres ODBC Driver
> > >> UserId=postgres
> > >> Password=XXX
> > >> Servername=localhost
> > >> Database=draft
> > >> Port=5432
> > >>
> > >> [/code]
> > >>
> > >>
> > >> What is the best way to proceed?
> > >
> > >
> > > is the last column empty or null?
> > >
> > > if not null then there is data there.
>
> 3754 while( ( ret = SQLGetData( m_hstmt, 3,
> SQL_C_WCHAR, included.get(), 255, &ind[2] ) ) != SQL_NO_DATA )
> (gdb) n
> 3756 if( ret == SQL_SUCCESS || ret == SQL_SUCCESS_WITH_INFO )
> (gdb) p ind[2]
> $1 = 4
> (gdb) n
> 3758 auto numBytes = ind[2];
> (gdb)
> 3759 if( ind[2] == SQL_NO_TOTAL )
> (gdb)
> 3761 else if( ind[2] > 255 )
> (gdb)
> 3763 str_to_uc_cpy( includedCol, included.get() );
> (gdb)
> 3764 }
> (gdb)
> 3754 while( ( ret = SQLGetData( m_hstmt, 3,
> SQL_C_WCHAR, included.get(), 255, &ind[2] ) ) != SQL_NO_DATA )
> (gdb)
> 3771 includedCol.erase( 0, 1 );
> (gdb) p ind[2]
> $2 = 4
> (gdb) p ret
> $3 = 100
> (gdb) n
>
> This is what happens with column 3 when the array is empty.
>
> 3779 while( ( ret = SQLGetData( m_hstmt, pos, SQL_C_WCHAR,
> index_param.get(), 255, &ind[3] ) ) != SQL_NO_DATA )
> (gdb)
> 3781 if( ret == SQL_SUCCESS || ret == SQL_SUCCESS_WITH_INFO )
> (gdb) p ind[3]
> $4 = -1
> (gdb) p ret
> $5 = 0
> (gdb) n
> 3783 auto numBytes = ind[3];
> (gdb)
> 3784 if( ind[3] == SQL_NO_TOTAL )
> (gdb)
> 3786 else if( ind[3] > 255 )
> (gdb)
> 3788 str_to_uc_cpy( options, index_param.get() );
> (gdb)
> 3789 }
> (gdb)
> 3779 while( ( ret = SQLGetData( m_hstmt, pos, SQL_C_WCHAR,
> index_param.get(), 255, &ind[3] ) ) != SQL_NO_DATA )
> (gdb)
> 3781 if( ret == SQL_SUCCESS || ret == SQL_SUCCESS_WITH_INFO )
> (gdb) p ind[3]
> $6 = -1
> (gdb) p ret
> $7 = 0
> (gdb)
>
> And this one is for column 4 of the query.
>
> The column is NULL, so no data is there.
>
> I think it's a bug in the driver as it should return SQL_NO_DATA on
> the very first call....
>
> Thank you.

Using following:

[quote]
WaylandGnome /home/igor/dbhandler/Debug # emerge -pv psqlodbc
* Last emerge --sync was 1y 348d 19h 34m 58s ago.

* IMPORTANT: config file '/etc/portage/package.keywords' needs updating.
* See the CONFIGURATION FILES and CONFIGURATION FILES UPDATE TOOLS
* sections of the emerge man page to learn how to update config files.

These are the packages that would be merged, in order:

Calculating dependencies... done!
Dependency resolution took 30.63 s (backtrack: 0/20).

[ebuild R ] dev-db/psqlodbc-11.01.0000::gentoo USE="ssl -doc
-iodbc -threads" 0 KiB

Total: 1 package (1 reinstall), Size of downloads: 0 KiB
WaylandGnome /home/igor/dbhandler/Debug #
[/quote]

Thank you.

>
> > >
> > > Dave