Created: 2012-03-26 13:33
Updated: 2019-01-15 22:09
License: mit


This gem allows resetting the id of an AR table to 0. It is useful after a delete_all command. It works in Postgres, Sqlite and MySQL up to now.


Add this line to your application's Gemfile:

gem 'activerecord-reset-pk-sequence'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activerecord-reset-pk-sequence


This gem adds a method to the class ActiveRecord::Base. Now it is shown an example of how it works.

The first thing is to install the gem as it is explained before.

After that you need a model. If you don't have one you can create it directly with rails as shown.

rails g model Person name:string

Then you do a database migration with:

rake db:migrate

To test the gem you have to start a rails console:

rails c

And then write the following commands:

p = Person.create(:name => 'David')
p = Person.create(:name => 'James')

You will see that the have the id's 1 and 2, then delete all elements in the table


If you create a new person now you will notice that the id is going to be 3

p = Person.create(:name => 'Peter')
id =
=> 3 

And this is what this gem is for, to reset the id's after deleting the elements in a table, to check if it works delete all elements and then run reset_pk_sequence method, after that create a new "Person" and check if its id is 1.

p = Person.create(:name => 'Jhon')

So to sum up to use this gem you only have to add the call to the new method after deleting all the elements in a table.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request
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