On Mon, Jun 18, 2012 at 7:38 AM, tanizawa <[email protected]> wrote:
> hi
>
> I am tanizawa
> I am searching how to add reference of two same table.
> Please teach me how to add .
> exmple:
> class CreateLocationjs < ActiveRecord::Migration
> def change
> create_table :locationjs do |t|
> t.references :locationm <----start point
> <--- I want to add end point
> field.
>
Not sure what your exact question is, but this example below
references a location 2 times:
# Create models:
rails g model location name:string
rails g model route
# Add associations between models:
in Location, add:
has_many :routes
in Route, add:
belongs_to :location_start, :class_name => Location, :foreign_key
=> "location_start_id"
belongs_to :location_end, :class_name => Location, :foreign_key
=> "location_end_id"
# Define foreign keys in db migration:
class CreateRoutes < ActiveRecord::Migration
def change
create_table :routes do |t|
t.references :location_start
t.references :location_end
t.timestamps
end
end
end
# Now in console:
munich = Location.new
munich.name = "Munich"; munich.save!
tokyo = Location.new
tokyo.name = "Tokyo"; tokyo.save!
route = Route.new
route.location_start = munich
route.location_end = tokyo
route.save!
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