Question

我正在使用Rails 5.我想从表中删除一堆记录。我有

currencies = CryptoCurrency.order('latest_market_cap_in_usd desc').limit(num_currencies)
current_index_currencies = CryptoIndexCurrency.all.pluck(:crypto_currency_id)

currencies_to_remove = current_index_currencies - currencies
...
currencies_to_remove.each do |currency|
  currency.destroy
end

其中＆＃34; currency_to_remove＆＃34;应该包含我想要删除的所有模型的数组。但是在迭代列表时我得到以下错误

2.4.0 :005 > svc.create_index
   (0.4ms)  SELECT "crypto_index_currencies"."crypto_currency_id" FROM "crypto_index_currencies"
  CryptoCurrency Load (1.5ms)  SELECT  "crypto_currencies".* FROM "crypto_currencies" ORDER BY latest_market_cap_in_usd desc LIMIT $1  [["LIMIT", 12]]
NoMethodError: undefined method `destroy' for 1020:Integer
    from /Users/davea/.rvm/gems/ruby-2.4.0/gems/whenever-0.9.7/lib/whenever/numeric.rb:10:in `method_missing'
    from /Users/davea/Documents/workspace/cindex/app/services/crypto_index_service.rb:17:in `block in create_index'
    from /Users/davea/Documents/workspace/cindex/app/services/crypto_index_service.rb:16:in `each'
    from /Users/davea/Documents/workspace/cindex/app/services/crypto_index_service.rb:16:in `create_index'
    from (irb):5
    from /Users/davea/.rvm/gems/ruby-2.4.0/gems/railties-5.0.4/lib/rails/commands/console.rb:65:in `start'
    from /Users/davea/.rvm/gems/ruby-2.4.0/gems/railties-5.0.4/lib/rails/commands/console_helper.rb:9:in `start'

Answer 1

那是因为currencies_to_remove包含要删除的模型的索引，而不是模型。因此，destroy方法未定义。

删除它们的最快方法是在模型类上使用delete方法：

CryptoCurrency.delete(currencies_to_remove)

但是如果你需要在destroy上调用回调，你可能需要destroy方法：

CryptoCurrency.destroy(currencies_to_remove)

注意，如果找不到指定数组中的任何记录，destroy方法将引发RecordNotFound异常

删除模型对象数组的最快方法是什么？

1 个答案: