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=head1 ADO specific attributes


=head2 ado_commandtimeout (all handles, decimal, inherited)

This attribute indicates the time (in seconds) after which a command is
canceled.
Typically, cancellation may occur during a long running C<execute> method.
Not all ADO providers support this functionality.
Whereas ADO's Command object doesn't inherit the Connection's CommandTimeout
setting, DBD::ADO's statement handle is initialized with the ado_commandtimeout
attribute of its associated database handle.


=head1 LOB support

Since version 2.92, DBD::ADO supports the DBI handle attributes C<LongReadLen>
and C<LongTruncOk>.
C<LongReadLen> defaults to C<2147483647> (for backwards compatibility).

For multibyte strings, it's unspecified whether C<LongReadLen> means I<bytes>
or I<characters>. It's passed through to ADO's C<GetChunk> method and
C<ActualSize> property.

B<Caveat:> Unexpected truncation errors may occur if the ADO provider (e.g.
Microsoft.Jet.OLEDB.4.0) uses I<bytes> for C<ActualSize> but I<characters>
for C<GetChunk>.

B<Caveat:> The ADO provider may have problems if the long field isn't the last
one in the list of selected columns, e.g.:

  Description : Catastrophic failure
  HelpContext : 5000000
     HelpFile :
  NativeError :
       Number : -2147418113
       Source : Microsoft JET Database Engine
     SQLState :

The (experimental) C<blob_read> method ignores the C<$offset> argument for
long fields (ADO maintains a I<current offset> internally). To ensure that
C<blob_read> reads from the beginning, C<LongReadLen> must be set to C<0>.


=head1 CAVEATS

=head2 Character set

Proper Unicode support depends on all components involved in your
application: the DBMS, the ADO provider, Perl and some perl modules.

In short: Perl 5.8 and Win32::OLE 0.16 (or later) are strongly
recommended and Win32::OLE has to be prepared to use the correct
codepage:

  Win32::OLE->Option( CP => Win32::OLE::CP_UTF8 );

More detailed notes can be found at

  http://purl.net/stefan_ram/pub/perl_unicode_en

=head2 ADO providers

=over

=item SQLOLEDB may truncate inserted strings

It seems that the size of the first inserted string is sticky.
Inserted strings longer than the first one are truncated.

As a workaround, the C<ado_size> attribute for C<bind_param> was
introduced in version 2.95:

  $sth->bind_param( $p_num, $bind_value, { ado_size => $size } );

=item MSDAORA may have problems with client-side cursors

MSDAORA may throw an error, return an empty result set or loop forever
when C<CursorLocation> is set to C<adUseClient>.
This setting is used in catalog methods for sorting and filtering.

=back


=head1 AUTHORS

Tim Bunce and Phlip. With many thanks to Jan Dubois and Jochen Wiedmann
for additions, debuggery and general help.
Special thanks to Thomas Lowery, who maintained this module 2001-2003.
Current maintainer is Steffen Goeldner.


=head1 SUPPORT

This software is supported via the dbi-users mailing list.
For more information and to keep informed about progress you can join the
mailing list by sending a message to dbi-users-help@perl.org

Please post details of any problems (or changes you needed to make) to
dbi-users@perl.org and CC them to me (sgoeldner@cpan.org).


=head1 COPYRIGHT

  Copyright (c) 1998, Tim Bunce
  Copyright (c) 1999, Tim Bunce, Phlip, Thomas Lowery
  Copyright (c) 2000, Tim Bunce, Thomas Lowery
  Copyright (c) 2001, Tim Bunce, Thomas Lowery, Steffen Goeldner
  Copyright (c) 2002, Thomas Lowery, Steffen Goeldner
  Copyright (c) 2003, Thomas Lowery, Steffen Goeldner
  Copyright (c) 2004-2011 Steffen Goeldner

  All rights reserved.

  You may distribute under the terms of either the GNU General Public
  License or the Artistic License, as specified in the Perl README file.


=head1 SEE ALSO