How do you adjust the scope of activerecord Association in rails 3- How do you scope ActiveRecord associations in Rails 3?

problem ：

I have a Rails 3 project. I have one Rails 3 project .With Rails 3 came Arel and the ability to reuse one scope to build another. With Rails 3,Arel You can reuse one scope to build another .I am wondering if there is a way to use scopes when defining a relationship (eg a "has_many"). I want to know if there is a way to use scope when defining relationships （ for example “has_many”）.

I have records which have permission columns. I have records , There are permission columns .I would like to build a default_scope that takes my permission columns into consideration so that records (even those accessed through a relationship) are filtered. I want to build a default_scope, It takes my permission column into account , In order to filter records （ Even records accessed through relationships ）.

Presently, in Rails 3, default_scope (including patches I've found) don't provide a workable means of passing a proc (which I need for late variable binding). at present , stay Rails 3 in ,default_scope（ Including the patch I found ） No delivery provided proc It's a feasible way （ I need late variable binding ）.Is it possible to define a has_many into which a named scope can be passed? Is it possible to define a that can pass a named range has_many？

The idea of reusing a named scope would look like: The idea of reusing named ranges is as follows ：

Orders.scope :my_orders, lambda{where(:user_id => User.current_user.id)}has_many :orders, :scope => Orders.my_orders

Or implicitly coding that named scope in the relationship would look like: Or the content of the named range in the implicit encoding relationship is as follows ：

has_many :orders, :scope => lambda{where(:user_id => User.current_user.id)}

I'm simply trying to apply default_scope with late binding. I'm just trying to default_scope Apply to late binding .I would prefer to use an Arel approach (if there is one), but would use any workable option. I prefer to use it Arel Method （ If any ）, But I will use any feasible option .

Since I am referring to the current user, I cannot rely on conditions that aren't evaluated at the last possible moment, such as: Because I mean the current user , So I can't rely on the conditions that haven't been evaluated at the last moment , for example ：

has_many :orders, :conditions => ["user_id = ?", User.current_user.id]

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Solution ：

Reference resources ： https://stackoom.com/en/question/A7Yi