Martin,

You want to make sure you require dm-validations. If you check object.errors you should see all the errors in the object reported. DataMapper reflects on the model definition you provide and sets up validations for all the properties.

If you were just using dm-core, you're only pulling in one piece of the ORM that handles persistence. DataMapper's pieces are decoupled so that you only require what you need. There is a datamapper metagem that pulls in the default "stack" for you, and will include dm-validations among other plugins.

Dan

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