Add an identity map to ActiveRecord
Like in DataMapper.
Mario T. Lanza commented
This is above all the greatest shortcoming to AR. It's almost a deal breaker and has me evaluating Sequel and other ORMs for an upcoming project. In one project I am working with highly intertwined database structures. The same records are frequently reloaded due to the way the business objects are navigated. Identity Map could solve this headache.
Now above simple code fails if parent and child records are created via nested forms (Rails 2.3 feature). I hope that with identity map, child records could have a reference to the parent object which exists only in memory. So validations like above and other non-trivial code also works.
Venkat K commented
I have AR objects which have parent child relationships (many are nested sets but even otherwise there are two or three level table relationships) this is becoming a important necessity
Parental Kontrol could be one useful plugin to give some relieve onw
Luismi Cavallé commented
I wasn't used to miss this functionality but lately I periodically get into advanced issues were i'd be really nice to have identity map in ActiveRecord. I also think some internals of ActiveRecord would be simplified and so further maintenance.
Otto Hilska commented
Not having an identity map forces me to write ugly hacks to avoid the performance problems.