lib/DBMerge.pm 

has verbose         => ( is => 'ro', default => 0 );
has dump_width      => ( is => 'ro', default => 80 );
has source_dsn      => ( is => 'ro', required => 1 );
has target_dsn      => ( is => 'ro', required => 1 );
has source_db_user  => ( is => 'ro' );
has target_db_user  => ( is => 'ro' );

has source_db_attr  => (
    is      => 'ro',
    lazy    => 1,
    default => sub { {}; },
);