Retroactively adding the primary key to a table

Question

I wrote a migration for a join model which looks like:

  create_table "project_memberships", :id => false, :force => true do |t|
    t.integer  "user_id"
    t.integer  "project_id"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
    t.integer  "id"
  end

I want to forcibly create ids now. Must I drop the table and recreate it or can I write a migration removing this constraint?

possible duplicate of [how to add a primary key to a table in rails](http://stackoverflow.com/questions/9644509/how-to-add-a-primary-key-to-a-table-in-rails) — ABMagil, Nov 09 '14 at 15:52
Thanks for the note, @ABMagil. I want to leave this question here because in my case there was already an `id` column (which is not true in your link). However, I am open to closing it if this isn't a significant difference to the StackOverflow community. — Eric Baldwin, Nov 09 '14 at 17:53

score 2 · Accepted Answer · edited May 23 '17 at 12:17

2

With a small amount of googling... http://thinkwhere.wordpress.com/2009/05/09/adding-a-primary-key-id-to-table-in-rails/

Generate a empty migration:

rails generate migration AddIdToProjectMemberships

and fill it in with:

def change
    add_column :project_memberships, :id, :primary_key
end

Also there was a question like this before.. how to add a primary key to a table in rails

edited May 23 '17 at 12:17

Community

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answered Mar 19 '13 at 22:48

Zippie

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Sorry, I didn't think to use the term primary key in my searches. Thanks! – Eric Baldwin Mar 19 '13 at 22:59

Retroactively adding the primary key to a table

1 Answers1