On migration I get the following error message:
PG::UndefinedTable: ERROR: relation "actioncodes" does not exist
: ALTER TABLE "organizations" ADD CONSTRAINT "fk_rails_4ecaa2493e"
FOREIGN KEY ("actioncode_id")
REFERENCES "actioncodes" ("id")
I have the following migration file for Organizations:
class CreateOrganizations < ActiveRecord::Migration
def change
create_table :organizations do |t|
t.string :name, null: false, limit: 40
t.references :actioncode, index: true, foreign_key: true
t.boolean :activated
t.datetime :activated_at
t.timestamps null: false
end
end
end
And for Actioncodes I have the migration file:
class CreateActioncodes < ActiveRecord::Migration
def change
create_table :actioncodes do |t|
t.string :code, null: false, limit: 20
t.string :description, limit: 255
t.timestamps null: false
end
end
end
class AddIndexToActioncodesCode < ActiveRecord::Migration
def change
add_index :actioncodes, :code, unique: true
end
end
The organization model file includes: belongs_to :actioncode
.
While the actioncodes model file includes: has_many :organizations
.
Any idea what could be causing the error message?
If I remove index: true, foreign_key: true
from the migration file, it migrates without errors. And when I replace that line with the incorrect line t.references :actioncode_id, index: true, foreign_key: true
, it gives the error below, where the last line ("ids") suggests Rails somehow seems to have problem with the name of the table?
PG::UndefinedTable: ERROR: relation "actioncode_ids" does not exist
: ALTER TABLE "organizations" ADD CONSTRAINT "fk_rails_604f95d1a1"
FOREIGN KEY ("actioncode_id_id")
REFERENCES "actioncode_ids" ("id")
So the issue is happening because CreateOrganizations
migration is being run before CreateActioncodes
is executed.
CreateActioncodes
is to be run first thereby ensuring that the action codes
table exists.
The order in which migrations are run is based on the time stamp of the migration - as indicated in the name of the file. 20141014183645_create_users.rb
will run before 20141014205756_add_index_to_users_email.rb
as the timestamp of the second one - 20141014205756
is after that of the first one - 20141014183645
.
Make sure the time-stamps of the CreateOrganizations
migration is after that of CreateActioncodes
migration.
Either you could manually change the timestamp in the file names. Or delete these migration files, and create them in the correct order.
The foreign_key: true
in this line:
t.references :actioncode, index: true, foreign_key: true
tells Rails to create a foreign key inside the database. A foreign key:
constraint specifies that the values in a column (or a group of columns) must match the values appearing in some row of another table. We say this maintains the referential integrity between two related tables.
So it is some logic inside the database (where it belongs) that ensures you can't put invalid values in your actioncode
column and that you can't remove entries from the actioncodes
table that are being used elsewhere.
In order to create the constraint, the referenced table (actioncodes
) needs to exist before you refer to it. Looks like your migrations are trying to create organizations
before actioncodes
so all you need to do is rename the CreateOrganizations
migration file so that its timestamp prefix comes after the one for CreateActioncodes
. The prefix is just a timestamp in the format YYYYMMDDhhmmss so change the CreateOrganizations
timestamp to the CreateActioncodes
timestamp with one more second.
I was also getting this error. If you are using a test database to run rspec make sure you run rake db:test:prepare
in the terminal before running rspec.
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