Emma, > In my current project the vast majority of DB access is blindingly > simple, the sort of problem that scaffolding can actually solve (at > least for the moment). I do, however, have a few queries that need in > DB reporting - I need to iterate over a set of objects, joining on to > a table and retrieving a count for joined objects for each row in the > first set. (actually, this is a simplification) > > For now I have actually implemented this in an n+1 query style, with a > ruby loop. Unpleasant and unscalable, but works for me right now.
There is the dm-aggregates gem for simple count(), sum(), min(), max (), avg() functions scoped to a Model or a Collection. It can even perform multiple aggregate functions in a single call with the aggregate() method. It only works with RDBMS' right now, but I would love to see someone add a layer that does it via "brute force" -- not all storage engines have the concept of aggregate functions, so there would be the need to iterate over every row and aggregate the results that way. Dan (dkubb) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "DataMapper" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/datamapper?hl=en -~----------~----~----~----~------~----~------~--~---
