When you want to add a string type column with a limited length with the `rails generate migration` command

You can do something like string {n}.

$ rails g migration AddNameToUsers name:string{30}

The generated migration file will be as follows

class AddNameToUsers < ActiveRecord::Migration[6.0]
  def change
    add_column :users, :name, :string, limit: 30

You can also use uniq and index, but note that I forget only limit for some reason.


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