CODEWITHSUNDEEP
ruby-on-railsmodelmigrationrake
Luigi
Luigi

Reputation: 5603

Attempted to Recreate Rails model, migrations messed up

I had a rails Model List.

I typed rails d model list in my terminal, resulting in this:

  invoke  active_record
  remove    db/migrate/20140116161958_create__lists.rb
  remove    app/models/list.rb
  invoke    rspec
  remove      spec/models/list_spec.rb

Then I typed rails g model list name:string size:integer which gave me this:

  invoke  active_record
  create    db/migrate/20140213155321_create_lists.rb
  create    app/models/list.rb
  invoke    rspec
  create      spec/models/list_spec.rb

Now, running rake db:migrate gives me this:

==  CreateLists: migrating ===============================================
-- create_table(:lists)
rake aborted!
An error has occurred, this and all later migrations canceled:

PG::DuplicateTable: ERROR:  relation "lists" already exists

The issue is that my table was not deleted from my DB. I can't roll back the migration that created that table, because it was destroyed when i ran rails d model list.

I could create a new migration and drop the table, but it would be placed after my migration created when I ran rails g model list..., so I assume it would error too.

Is my only choice to delete the model again, create a migration to drop the table, then recreate the model?

Also, in the future, how should one go about deleting and recreating a model? Roll back the migration prior to rails d model?

Upvotes: 0

Views: 426

Answers (1)

Rahul Singh
Rahul Singh

Reputation: 3427

1>

before running rails d model list

run

$ rake db:migrate:down VERSION=20140116161958

will roll back the list file to remove table lists from database.

2>

but since u have already destroyed your model what u can do is delete table lists from rails database console. try this

$ rails dbconsole # from your app root path

and then type drop table lists;

3>

you can drop your table from rails console also

$rails console

Then just type:

ActiveRecord::Migration.drop_table(:lists)

4>

also u can create a migration file to drop your table :

$ rails generate migration DropListsTable

this will create an empty migration file now edit that file to look like:

class DropListsTable < ActiveRecord::Migration
  def up
    drop_table :lists
  end

  def down
    raise ActiveRecord::IrreversibleMigration
  end
end

then run $ rake db:migrate

Upvotes: 4

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