如何从2多个关系中查找关联记录

Question

我有以下型号

Business has many Categories through Categorizations
Category has many Businesses through Categorizations

Business has many Estates through Localizations
Estate has many Businesses through Localizations

我如何找到某个地产的所有业务类别？

@categories =查找某个地产业务的所有类别

Answer 1

必须有一种更简单的方法，但您可以随时尝试：

@estate = Estate.find(1)

@estate.businesses.map {|business| business.categories}.flatten

或

@estate = Estate.find(1)

@categories = Categories.where(id: @estate.businesses.pluck(:id))