method

up_only

v5.2.3 - Show latest stable - 0 notes - Class: ActiveRecord::Migration

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What's this?

up_only() public

Used to specify an operation that is only run when migrating up (for example, populating a new column with its initial values).

In the following example, the new column published will be given the value true for all existing records.

class AddPublishedToPosts < ActiveRecord::Migration[5.2]
  def change
    add_column :posts, :published, :boolean, default: false
    up_only do
      execute "update posts set published = 'true'"
    end
  end
end

Show source

# File activerecord/lib/active_record/migration.rb, line 752
    def up_only
      execute_block { yield } unless reverting?
    end

up_only

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