What are some good or bad design decisions in ActiveRecord's implementation?

Question

I'm interested in learning more about how ActiveRecord was designed and why particular decisions were made along the way that led to the implementation that we have now.

Could anyone provide some examples of good or bad design decisions that were made in ActiveRecord's implementation?

Answer 1

The largest design decision I can think of off the top of my head is AR's "dynamic" models, where it creates fields based on the return of your query, as opposed to a Django and Catalyst preferred style "static" where you list the fields in the code and it requests those things when it runs the query (Catalyst supports dynamic models as well, but they aren't encouraged.). The "dynamic" is less verbose, while the "static" decouples the DB structure from the code structure.