我如何将其转换为 MetaWhere 或 Arel？

发布于 2024-11-02 16:41:09 字数 584 浏览 5 评论 0原文

考虑一个城市模型具有：

  def self.search(field, search)
    if search
      where("#{field} LIKE ?", "%#{search}%")
    else
      scoped
    end
  end

在知道该字段是字符串的情况下如何使用 Arel 或 Metawhere 可以具有类似：

“名称”的内容 “居民姓名” “state.name”

我想做类似的事情（行不通）：

  def self.search(field, search)
    if search
       where(field =~ "%#{search}%")
    else
      scoped
    end
  end

那么，你的想法是什么？

真正的问题是，我怎样才能将其转换为：

“residents.name LIKE '#{value}%'”

到：

:residents => { :name =~ "#{value}%" }

原文

Consider a City Model having:

  def self.search(field, search)
    if search
      where("#{field} LIKE ?", "%#{search}%")
    else
      scoped
    end
  end

How can I use Arel or Metawhere in that situation knowing that field is a String can have anything like:

"name"
"residents.name"
"state.name"

I want to do something like that (will not work):

  def self.search(field, search)
    if search
       where(field =~ "%#{search}%")
    else
      scoped
    end
  end

So, what are your thoughts?

The real question is, how can I convert that:

"residents.name LIKE '#{value}%'"

To that:

:residents => { :name =~ "#{value}%" }

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雄赳赳气昂昂 2024-11-09 16:41:09

你应该能够像这样使用 Arel。

def self.search(field, search)
  if search
    if field =~ /\./ # table and field
      table, field = field.split('.')
      arel_join = table.singularize.camelize.constantize.arel_table
      joins(table.to_sym).where(arel_join[field].matches("%#{search}%"))
    else
      where(Resource.arel_table[field].matches("%#{search}%"))
    end
  else
    scoped
  end
end

有一个 Railscast 很好地解释了以下基础知识在 Rails 3 中使用 Arel。

You should be able to use Arel like this.

def self.search(field, search)
  if search
    if field =~ /\./ # table and field
      table, field = field.split('.')
      arel_join = table.singularize.camelize.constantize.arel_table
      joins(table.to_sym).where(arel_join[field].matches("%#{search}%"))
    else
      where(Resource.arel_table[field].matches("%#{search}%"))
    end
  else
    scoped
  end
end

There's a Railscast that does a good job of explaining the basics of using Arel in Rails 3.

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