Ruby-on-rails – Specifying column name in a “references” migration

activerecordrails-migrationsruby-on-railsruby-on-rails-3

I want to make a migration in Rails, referencing another table. Usually, I would do something like:

add_column :post, :user, :references

This creates a column named user_id in posts table. But what if, instead of user_id, I want something like author_id? How can I do that?

For Rails 5+

If you are defining your Post model table, you can set references, index and foreign_key in one line:

t.references :author, index: true, foreign_key: { to_table: :users }

If you are adding references to an existing table, you can do this:

add_reference :posts, :author, foreign_key: { to_table: :users }

^{Note: The default value for index is true.}

def change
  change_column_default( :table_name, :column_name, from: nil, to: false )
end

def up
  change_column_default( :table_name, :column_name, nil )
end

def down
  change_column_default( :table_name, :column_name, false )
end