Dearest Monks, I am just getting my feet wet with DBD::Mock. I've read through the POD for the module and also have read an excellent article on Perl.com - Perl Code Kata: Testing Databases. However I'm getting tripped up on an aspect of the DBD::Mock::Session object. When you create your statement, result pairs you can can have statement point to a CODE ref. The documentation says this can be used as a sort of catch all but I'm not able to grasp a good example of using this. I found this example:

 
statement => sub { 
      my $parser1 = SQL::Parser->new('ANSI');
      $parser1->parse(shift(@_)); 
      my $parsed_statement1 = $parser1->structure(); 
      delete $parsed_statement1->{original_string};
      
      my $parser2 = SQL::Parser->new('ANSI');
      $parser2->parse("UPDATE users SET login_failures = 
           (login_failures + 1) WHERE user_id = 1");
      my $parsed_statement2 = $parser2->structure(); 
      delete $parsed_statement2->{original_string};      
      
      return Dumper($parsed_statement2) eq Dumper($parsed_statement1);
  },
  results   => [[ 'rows' ], []]
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However, I'm guessing if it finds parser2 statement and matches the supplied statement returns a true result. What are some other good examples/needs of using a ref to the statement key? (just trying to understand this functionality)