First of all, you need to be consistent in which directory level you use as the base package name. I see you have bar::bar1, but also a plain bar, even though they're located in the same directory. In other words, your bar package ought to read like this:

package bar::bar;
use base 'Class::DBI';
1;
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For the relationships, you're supposed to use the full package name, so

__PACKAGE__->has_many(barf    => 'bar::bar2');
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I don't think you're actually supposed to use() your subclasses inside your base class either.