WARNING: This gem is NOT sanctioned by the DataMapper team. Use at your own risk.

If you use this gem and find any issues, please let me know. Also, if you use this gem and things seem to be working just fine, then please let me know that too. Good luck!

DataMapper-0.3.0.1.gem

In the gem at the bottom of lib/data_mapper/support/typed_set.rb there is the following code:

class Class
  include Comparable
  def <=>(other)
    name <=> other.name
  end
end

This causese Test::Runner to through up an error similar to this:

/usr/local/lib/ruby/1.8/test/unit/collector/objectspace.rb:25:in `collect': undefined method `suite' for Gem::LoadError:Class (NoMethodError)
from /usr/local/lib/ruby/1.8/test/unit/collector/objectspace.rb:23:in `each_object'
from /usr/local/lib/ruby/1.8/test/unit/collector/objectspace.rb:23:in `collect'
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:58
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:213:in `[]'
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:213:in `run'
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:12:in `run'
from /usr/local/lib/ruby/1.8/test/unit.rb:278
from /usr/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake/rake_test_loader.rb:5
rake aborted!

It also causes your tests to blow up and not run. Which, if you’re trying to do any development causes some real problems! If you comment out ‘include Comparable’ from Class things seem to work just fine. I say seem, because I haven’t done any real extensive testing with this. The other thing you can do is revert to 0.2.5, but that’s up to you. Either way, it’s not really optimal. Let’s hope they fix this soon.

I will say DataMapper is clean, simple, and feature rich. In 0.3.0 they’ve added migrations, which is great. Btw, a little off topic, but I’m working on migration support for both ActiveRecord and DataMapper in Mack as we speak. It should, hopefully, be out sometime this week. What I won’t give DataMapper is that it’s fast. In my tests, and I’ll provide some number below, DataMapper only seems to win on inserts, after that ActiveRecord beats it hands down. In all fairness to DataMapper I’m starting to think that the problems are not at the DataMapper layer, but at the underlying Data Objects layer that DataMapper uses. As you’ll see from my tests DataMapper seems very heavily optimized towards MySQL over PostgreSQL. This, to me, leans towards a difference in the underlying adapters.

Another problem I have with DataMapper is that I have to set the ‘properties’ of the model inside the model itself. It’s an old school approach, and it does have the benefit of being self documenting, but it also has the drawbacks of constant maintenance and clutter at the top of your model. Not to mention potential conflicts when running through migrations, etc…

I’m also having one other little problem these days. This has only been a problem since I’ve gone DataMapper 0.3.0. At the end of some of rake tasks, if I have DataMapper required, I get this:

 

/usr/local/lib/ruby/1.8/test/unit/collector/objectspace.rb:25:in `collect': undefined method `suite' for Gem::VerificationError:Class (NoMethodError)
from /usr/local/lib/ruby/1.8/test/unit/collector/objectspace.rb:23:in `each_object'
from /usr/local/lib/ruby/1.8/test/unit/collector/objectspace.rb:23:in `collect'
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:58
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:213:in `[]'
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:213:in `run'
from /usr/local/lib/ruby/1.8/test/unit/autorunner.rb:12:in `run'
from /usr/local/lib/ruby/1.8/test/unit.rb:278

The rake task completed successfully, but I get this fairly random error message. If anyone out there is also getting this message, please let me know what it is. I’m open for ideas on this one.

Despite these issues I have with DataMapper, I’m going to keep striving to provide support for both it and ActiveRecord in Mack. I think it’s important to give people a choice and not force them to use the one I think is either easier to code for, or better. Both of which I’m not saying about ActiveRecord, but in technologies in general.

Anyway, enough of my blather, here are the test results I was speaking about:

 

Running time 1.693881 seconds. [MESSAGE]: DM: postgresql: Inserts
Running time 2.799189 seconds. [MESSAGE]: AR: postgresql: Inserts

Running time 1.368185 seconds. [MESSAGE]: DM: postgresql: Individual Reads
Running time 0.734143 seconds. [MESSAGE]: AR: postgresql: Individual Reads

Running time 0.917551 seconds. [MESSAGE]: DM: postgresql: Bulk Reads
Running time 0.121198 seconds. [MESSAGE]: AR: postgresql: Bulk Reads

Running time 2.309244 seconds. [MESSAGE]: DM: postgresql: Updates
Running time 2.079578 seconds. [MESSAGE]: AR: postgresql: Updates

Running time 1.802914 seconds. [MESSAGE]: DM: postgresql: Deletes
Running time 1.708714 seconds. [MESSAGE]: AR: postgresql: Deletes

Running time 0.433761 seconds. [MESSAGE]: DM: mysql: Inserts
Running time 2.621093 seconds. [MESSAGE]: AR: mysql: Inserts

Running time 1.073741 seconds. [MESSAGE]: DM: mysql: Individual Reads
Running time 0.207305 seconds. [MESSAGE]: AR: mysql: Individual Reads

Running time 0.827842 seconds. [MESSAGE]: DM: mysql: Bulk Reads
Running time 0.073593 seconds. [MESSAGE]: AR: mysql: Bulk Reads

Running time 1.204845 seconds. [MESSAGE]: DM: mysql: Updates
Running time 1.738602 seconds. [MESSAGE]: AR: mysql: Updates

Running time 1.010774 seconds. [MESSAGE]: DM: mysql: Deletes
Running time 1.251691 seconds. [MESSAGE]: AR: mysql: Deletes