無法更新紅寶石環路內的數據庫

Question

此代碼顯示註冊，它顯示數據。

cids.each {|c_array| 
    puts c_array[0] 
    signup = Signup.first(:customer_id => c_array[0]) 
    #signup.created_at = c_array[1] 
    puts "signup is " + signup.inspect 
    #signup.update! 
    } 

結果：

signup is #<Signup @id=1 @user_id=1 @customer_id=74843293 @company_id=6 @created_at=Thu, 08 Jan 2015 22:21:43 -0500 @updated_at=Thu, 08 Jan 2015 22:21:43 -0500> 

signup is #<Signup @id=2 @user_id=1 @customer_id=67170279 @company_id=6 @created_at=Thu, 08 Jan 2015 22:21:43 -0500 @updated_at=Thu, 08 Jan 2015 22:21:43 -0500> 

signup is #<Signup @id=3 @user_id=1 @customer_id=69079324 @company_id=6 @created_at=Thu, 08 Jan 2015 22:21:44 -0500 @updated_at=Thu, 08 Jan 2015 22:21:44 -0500> 

signup is #<Signup @id=4 @user_id=1 @customer_id=60434274 @company_id=6 @created_at=Thu, 08 Jan 2015 22:21:44 -0500 @updated_at=Thu, 08 Jan 2015 22:21:44 -0500> 

等等。

但當我去掉了其他兩行：

cids.each {|c_array| 
    puts c_array[0] 
    signup = Signup.first(:customer_id => c_array[0]) 
    signup.created_at = c_array[1] 
    puts "signup is " + signup.inspect 
    signup.update! 
    } 

它打破：

NoMethodError - undefined method `created_at=' for nil:NilClass: 
    customerController.rb:49:in `block (2 levels) in <class:CustomerController>' 

任何想法？

Answer 1

看起來像你並不總是有Signup與customer_id從你的陣列，有時它返回nil而不是Signup對象。只需添加以下檢查：

cids.each do |c_array| 
    puts c_array[0] 
    signup = Signup.first(:customer_id => c_array[0]) 
    puts "signup is " + signup.inspect 
    unless signup.nil? 
    signup.created_at = c_array[1] 
    signup.update! 
    end 
end