问题
I have made a workout application with with the following models:
user
routine
lifts
exercises
infos
A routine belongs to a user
A routine has many lifts (which is a joins between exercise and routine)
A lift belongs to an exercise
Infos(sets) belong to a lift
I am digging into ActiveRecord Queries and specifically includes to work on the n+1 problems I am having. When I show the entire routine which shows:
The routines name
The users name
The exercise names for each lift
The sets for each lift
If I want to make less queries can I simply load up everything such as in the following:
a = Routine.includes(:user, :lifts, :exercises, :infos) and loop through all of that to find what I want?
Or do I have to break it down more say:
a = Routine.includes(:user, :lifts)
b = Lift.includes(:exercise, :infos)
in order to shrink the amount of queries I have.
If this question is not clear enough please let me know.
回答1:
Something like the following should work. Routine.includes(:user, {:lifts => [:exercise, :infos]})
来源：https://stackoverflow.com/questions/20108371/activerecord-includes