All,
We're trying to override the DBI->connect() method for DBD::DB2 to
support longer database names.
Some background:
- DB2 supports only 8-character database names and aliases
- We plan to have hundreds to thousands of them, so we end up with
non-intelligeble names.
- We have a mapping file that maps logical names (to us, which means
something like NYTD_YOUR_APPLICATION or LNQD_OTHER_APPLICATION) to
one of the 8-character names that DB2 limits us to.
The first approach we came up with was to define a "Morgan Stanley
DB2" driver, as that would allow us to avoid changing DBD::DB2.
Hence we wrote DBD::MSDB2, which basically sub-classes DBD::DB2:
package DBD::MSDB2;
use DBD::DB2;
use vars qw(@ISA $VERSION);
@ISA = qw(DBD::DB2::dr);
$VERSION = '1.0';
#
# Override the 'connect' class method
#
sub connect {
my ($drh, $dbname, $user, $auth, $attr) = @_;
# Look up the long database name, change $dbname, then...
$drh->SUPER::connect($dbname, $user, $auth, $attr);
}
and then we try and connect with:
DBI->connect('dbi:MSDB2:NYTD_YOUR_APPLICATION', $uid, $pwd);
This leads to the following error:
DBD::MSDB2 initialisation failed: Can't locate object method "driver" via package
"DBD::MSDB2" (perhaps you forgot to load "DBD::MSDB2"?) at
//ms/dist/perl5/PROJ/DBI/1.42-5.6/lib/perl5/DBI.pm line 727.
Okay, so change @ISA:
@ISA = qw(DBD::DB2 DBD::DB2::dr);
And the next error is:
Had to create DBD::MSDB2::dr::imp_data_size unexpectedly at
//ms/dist/perl5/PROJ/DBI/1.42-5.6/lib/perl5/DBI.pm line 1061. Use
of uninitialized value in subroutine entry at
//ms/dist/perl5/PROJ/DBI/1.42-5.6/lib/perl5/DBI.pm line 1061. Had
to create DBD::MSDB2::db::imp_data_size unexpectedly at
//ms/dist/perl5/PROJ/DBI/1.42-5.6/lib/perl5/DBI.pm line 1061. Use
of uninitialized value in subroutine entry at
//ms/dist/perl5/PROJ/DBI/1.42-5.6/lib/perl5/DBI.pm line 1061. DBD
driver has not implemented the AutoCommit attribute at
//ms/dist/perl5/PROJ/DBI/1.42-5.6/lib/perl5/DBI.pm line 631.
Obviously, I'm missing some clues on how to actually do this kind of
thing. Any suggestions?
