没有这样的功能：现在在迁移期间答案

【问题标题】：no such function: NOW during migration没有这样的功能：现在在迁移期间
【发布时间】：2017-04-28 05:40:48
【问题描述】：

在 Ruby on Rails 中，我正在为用户迁移创建一个可确认的设计，但是当我迁移时出现错误：

StandardError：发生错误，此迁移和所有后续迁移取消

SQLite3::SQLException：没有这样的功能：现在：更新用户集 Confirmed_at = NOW()

迁移：

class AddConfirmableToDevise < ActiveRecord::Migration[5.0]
  def up
    add_column :users, :confirmation_token, :string
    add_column :users, :confirmed_at, :datetime
    add_column :users, :confirmation_sent_at, :datetime
    # add_column :users, :unconfirmed_email, :string # Only if using reconfirmable
    add_index :users, :confirmation_token, unique: true
    # User.reset_column_information # Need for some types of updates, but not for update_all.
    # To avoid a short time window between running the migration and updating all existing
    # users as confirmed, do the following
    execute("UPDATE users SET confirmed_at = NOW()")
    # All existing user accounts should be able to log in after this.
    # Remind: Rails using SQLite as default. And SQLite has no such function :NOW.
    # Use :date('now') instead of :NOW when using SQLite.
    # => execute("UPDATE users SET confirmed_at = date('now')")
    # Or => User.all.update_all confirmed_at: Time.now
  end

  def down
    remove_columns :users, :confirmation_token, :confirmed_at, :confirmation_sent_at
    # remove_columns :users, :unconfirmed_email # Only if using reconfirmable
  end
end

【问题讨论】：

标签： ruby-on-rails devise sqlite

【解决方案1】：

引用你的问题：

# Use :date('now') instead of :NOW when using SQLite.
# => execute("UPDATE users SET confirmed_at = date('now')")

【讨论】：