Rails 3，多个数据库连接和设置模型

Question

When working with multiple database connections and setting up models to work with those different instances, how do you setup the has_many, has_one, belongs_to, etc?

For example:

I have one database that is Read + Write, the other DB instance is used in my Rails app as Read only. The DB table that is Read only I am pulling back a list of Media items (Videos, Images and Audios). In my Read + Write DB I have a media_ratings table.

I have a model called AvMedia (The Read only DB) and a MediaRating Model (Read + Write DB). How do I setup The AvMedia model like so: has_one rating and setup the MediaRating model like so: has_many AvMedia?

Sorry if this is confusing... I tried to explain it the best I could.

Answer 1

In the AvMedia model you must include has_one :rating and just make sure that in the corresponding table you have a rating_id foreign key. You also need belongs_to :avmedia in your rating model.

A lot of magic goes on behind the scenes to automatically link your tables together when you define a relationship.

It sounds like you don't need the has_many for AvMedia - from what you said it appears that it's a 1-1 relationship (one AvMedia has one rating, one rating corresponds with one AvMedia). If this is incorrect, let me know.