在Active Record中反向外键查找

Question

我正在尝试编写一个可以产生反向外键查找的方法。我们的想法是，给定单个Rails模型类，我可以反映获取所有ActiveRecord反射并提取父表名和外键。

这对于简单的has和has_many关系来说是微不足道的，即使是多态也是如此。我遇到的困难是处理关系。我不确定我是否需要将belongs_to作为用例处理。

这是我到目前为止的代码

def add_association(klass_name, association)
  associated_model = association.class_name
  @association_hash[klass_name][associated_model] ||= {}
  if association.is_a? ActiveRecord::Reflection::ThroughReflection
    add_through_reflection(klass_name, associated_model, association)
  elsif association.is_a? ActiveRecord::Reflection::AssociationReflection
    add_association_reflection(klass_name, associated_model, association)
  else
    raise "Unhandled ActiveRecord::Reflection association type"
  end
end

def add_association_reflection(klass_name, associated_model, association)
  return if association.macro == :belongs_to
  begin
    @association_hash[klass_name][associated_model][:macro] = association.macro
    @association_hash[klass_name][associated_model][:assocation_class] = association.class
    @association_hash[klass_name][associated_model][:assocation] = association
    @association_hash[klass_name][associated_model][:table_name] = association.klass.table_name
    @association_hash[klass_name][associated_model][:pk] = association.klass.primary_key
    @association_hash[klass_name][associated_model][:fk] = association.foreign_key
    @association_hash[klass_name][associated_model][:type] = klass_name if association.foreign_key != klass_name.underscore + "_id"
  rescue StandardError => e
    store_the_error(associated_model, e)
  end
end

add_through_reflection方法现在正在检索宏，association_class和关联。我通过ThroughReflection方法同时运行AssociationReflection和add_association_reflection，但ThroughReflection类型的pks和fks不正确。