How can I give foreign key a name in RoR?
I use following command to give foreign key:开发者_JAVA技巧
rails generate scaffold Table2 id:integer Table1:references
This command adds foreign key of Table1 in Table2
but with default name that is Table1_id
. So how can I give custom name to it for example my_table_f_key
instead of Table1_id
.
I'm using Ruby 1.9.2 and Rails 3.0.3.
Edit:-
In my project.rb
model:
belongs_to :own, :class_name => User
In my user.rb
model:
has_many :owned_projects, :class_name => Project, :foreign_key => :owner
how I created my project model
rails generate scaffold Project name:string owner:integer
Now when I access user_id from Project like
project.owner.userid
it throws exception.
Based on your responses in the comments, this is one way of implementing what you want to do:
Assuming two models in your app (Users and Questions), and two different relationships:
- User asks many Questions, Question belongs_to Asker
- User edits many Questions, Question belongs_to Editor
You could implement this structure in the following way:
rails generate scaffold Question asker_id:integer editor_id:integer
Specifying id:integer
in your generate command is redundant, as Rails will generate that column for you automatically. It's also conventional to name your foreign keys in terms of the relationship (ie, asker_id
).
Then, inside each of your models:
class Question < ActiveRecord::Base
belongs_to :asker, :class_name => User
belongs_to :editor, :class_name => User
end
class User < ActiveRecord::Base
has_many :asked_questions, :class_name => Question, :foreign_key => :asker_id
has_many :edited_questions, :class_name => Question, :foreign_key => :editor_id
end
That way, you can use them together like this:
@question.asker # => User
@question.editor # => User
@user.asked_questions # => [Question, Question, Question]
@user.edited_questions # => [Question, Question]
Hope this helps.
Adding to @Dan's answer, pass the class name as String.
DEPRECATION WARNING: Passing a class to the
class_name
is deprecated and will raise an ArgumentError in Rails 5.2. It eagerloads more classes than necessary and potentially creates circular dependencies. Please pass the class name as a string
class Question < ActiveRecord::Base
belongs_to :asker, :class_name => User
belongs_to :editor, :class_name => User
end
class User < ActiveRecord::Base
has_many :asked_questions, :class_name => 'Question', :foreign_key => :asker_id
has_many :edited_questions, :class_name => 'Question', :foreign_key => :editor_id
end
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