如何区分Ruby on Rails中Sphinx索引方法的差异？

本文共计343个文字，预计阅读时间需要2分钟。

想了解以下内容之间的区别：`shop.created_at` 和 `:as=created_at`，`:as=:created_at`，`:as=:created_at`。谢谢。所以，我的理解是，这些表达式可能在数据库查询中用于重命名列。第二和第三条语句看起来是重复的，而第一条语句可能是在指定列的别名。如果我的理解有误，请纠正。

想知道这些之间有什么区别：

indexes shop.created_at, :as =>created_at has shop(:created_at), :as => :created_at has shop.created_at, :as => :created_at

谢谢.

所以我不认为第二和第三之间存在差异(如果我错了,请纠正我！)但是,我确信第1和第2之间的区别

索引用于指定字段 – 根据Thinking Sphinx网站：

Fields are the content for your search queries – so if you want words tied to a specific document, you better make sure they’re in a field in your index. They are only string data – you could have numbers and dates and such in your fields, but Sphinx will only treat them as strings, nothing else.

has用于指定属性 – 再次,根据Thinking Sphinx网站：

Attributes are used for sorting, filtering and grouping your search results. Their values do not get paid any attention by Sphinx for search terms, though, and they’re limited to the following data types: integers, floats, datetimes (as Unix timestamps – and thus integers anyway), booleans, and strings. Take note that string attributes are converted to ordinal integers, which is especially useful for sorting, but not much else.