Hey folks, After a bit of a hiatus to deal with other things, I am back into my AW implementation.
For one of the fact tables I want to create, it is based off an AR model's table that uses a polymorphic relationship, so I am thinking about how to handle this using AW ETL. I'm thinking it would be best to denormalize this with a row processor, and looking for advice on how best to do it. To use my app as an example, we have an activity feed (think facebook feed, yes, I know, not original) that has the general form: ":user does :action to :action_object" The :user part is easy, this will be stored in the fact table as an id relating to the user dimension. The :action is a string value, so I'll probably create a dimension for this with all possible values, so this too will end up a reference to a dimension. (probably use the foreign key transform for this, right?) The :action_object is polymorphic, with 2 columns, :action_object_id, and :action_object_type. The row processor would: First, get all possible values for 'action_object_type', e.g. 'Foo', and 'Bar'. Map the type value to new columns per value, so 'foo_id' and 'bar_id' in this case will need to be added to each row. As each row is processed, if a row has the values action_object_type='Foo', and action_object_id=1, then the processor would add foo_id=1 and bar_id=nil. The assumption here is that there are corresponding dimensions for Foo and Bar to go with these new columns. Does this make sense? Has anyone else solved this a different way? Anyone interested in the polymorphic processor code once I finish it? (I am testing it now, but looking for validation before I move ahead using it) Cheers, Andrew Kuklewicz _______________________________________________ Activewarehouse-discuss mailing list Activewarehouse-discuss@rubyforge.org http://rubyforge.org/mailman/listinfo/activewarehouse-discuss
