在Heroku上运行迁移时，我得到PG :: Error：ERROR：关系“ member1_id”不存在

Question

Locally, my migrations are fine (although I'm using SQLite. Will switch to postgresql on development asap).

After resetting the database on Heroku with

heroku pg:reset DATABASE

I ran

heroku run rake db:migrate

But I am getting the following error after a migration:

==  AddForeignKeysToCollaborations: migrating =================================
-- change_table(:collaborations)
rake aborted!
An error has occurred, this and all later migrations canceled:

PG::Error: ERROR:  relation "member1_id" does not exist
: ALTER TABLE "collaborations" ADD CONSTRAINT "collaborations_member1_id_id_fk" FOREIGN KEY ("member1_id_id") REFERENCES "member1_id"(id) ON DELETE CASCADE

Here is that migration:

class AddForeignKeysToCollaborations < ActiveRecord::Migration
  def change
    change_table :collaborations do |t|
        t.foreign_key :member1_id, dependent: :delete
        t.foreign_key :member2_id, dependent: :delete
        end
  end
end

Previous migrations for Collaborations are

class CreateCollaborations < ActiveRecord::Migration
  def change
    create_table :collaborations do |t|
      t.integer :user_id
      t.integer :collaborator_id

      t.timestamps
    end
    add_index :collaborations, :collaborator_id
    add_index :collaborations, [:user_id, :collaborator_id], unique: true
  end
end

and

class UpdateCollaborations < ActiveRecord::Migration
  def change
    change_table :collaborations do |t|
      t.rename :user_id, :member1_id
      t.rename :collaborator_id, :member2_id
      t.string :status
    end
    add_index :collaborations,:member1_id
    add_index :collaborations,:member2_id
  end
end

Which are run in that order. Why is this error coming up on Heroku? Specifically, it looks like PG is adding an unnecessary "_id" to "member1_id"

Answer 1

You're calling foreigner's methods with the wrong arguments. The first argument is the referenced table name not the referencing column name. And since your column names don't nicely match the table names you'll need :column options as well. Something like this:

t.foreign_key :users, :column => :member1_id, :dependent => :delete

That assumes that :users is the table name that your :member1_id and :member2_id columns should be pointing at.

The error message:

relation "member1_id" does not exist

tells you that PostgreSQL is looking for a table called member1_id but can't find it.