Re: the return of tables ()

On Tue, Sep 02, 2008 at 12:39:41AM +0200, H.Merijn Brand wrote:
> On Mon, 1 Sep 2008 22:59:24 +0100, Tim Bunce <[email protected]>
> wrote:
> 
> > > > > > > As get_info (29) now returns a TRUE value, the 'tables ()' method is
> > > > > > > using a different strategy to build the list it returns:
> > > > > > > 
> > > > > > >     sub tables
> > > > > > >     {
> > > > > > >         my ($dbh, @args) = @_;
> > > > > > >         my $sth    = $dbh->table_info (@args[0..4]) or return;
> > > > > > >         my $tables = $sth->fetchall_arrayref or return;
> > > > > > >         my @tables;
> > > > > > > »       if ($dbh->get_info (29)) { # SQL_IDENTIFIER_QUOTE_CHAR
> > > > > > > »           @tables = map { $dbh->quote_identifier (@{$_}[0,1,2]) } @$tables;
> > > > > > > »           }
> > 
> > > > > > > Unify has no support for CATALOG's, so the values in info are not
> > > > > > > defined, but still used in the map, causing all my tables no showing up
> > > > > > > with and empty "". in front of it, which is illegal to the database :(

> > I wasn't very clear (and was actually partly misleading). Sorry.
> > 
> > What I meant was that the TABLE_CAT and/or TABLE_SCHEM columns in the
> > data returned by your table_info () method are probably empty strings but
> > should be undefs.
> > 
> > What does
> >     Data::Dumper::Dumper($dbh->table_info(...)->fetchall_arrayref)
> > show for an example table?
> 
> $ perl -Iblib/{lib,arch} -MPROCURA::DBD -MData::Dumper
> -wle'$dbh=DBDlogon;print Dumper $dbh->table_info(undef,"PROLEP","parm")->fetchall_arrayref' $VAR1 = [
>           [
>             '',
>             'PROLEP',
>             'parm',
>             'T',
>             'W'
>           ]
>         ];
> 
> Correct, as that is the result of
> 
> sub table_info
> {

>     my $sth = $dbh->prepare (
> 	"select '', OWNR, TABLE_NAME, TABLE_TYPE, RDWRITE ".
> 	"from   SYS.ACCESSIBLE_TABLES ".
> 	$where);

> select NULL, OWNR, ...
> 
> is not allowed. I don't see an easy way out
> 
> sql> select NULL, OWNR, TABLE_NAME
> sql>    from SYS.ACCESSIBLE_TABLES
> sql>    where TABLE_NAME like 'parm';
> NULL is not allowed in a constant list (-10518).

Perhaps you could use some expression that happens to yield a NULL.
Or you could implement a custom quote_identifier() method.

Tim.