当试图更新db值时，rails update_attributes返回false

Question

希望这里有人能指出我正确的方向。

我有一个控制器更新def运行“update_attributes”。目前它返回false，没有错误信息。我对Ruby相当陌生，但对编码不太熟悉，这让我难以忍受好几天！我正在尝试使用下面指定的值更新用户模型和数据库。

def update 
    #get currently logged in user 
    @user = current_user 
    #update user params based on edit form... 
    if @user.update_attributes(params[:user]) 
     redirect_to profile_path, :notice => "Successfully updated profile." 
    else 
     render :action => 'edit' 
    end 
end 

我的编辑DEF ....

def edit 
    @user = current_user 
end 

形式发送以下此更新方法：

--- !ruby/hash:ActiveSupport::HashWithIndifferentAccess 
utf8: ✓ 
_method: put 
authenticity_token: 9T4ihVI0p8j7pZEFxof3Bfahi2a+o3BPmtXJDnfHT4o= 
user: !ruby/hash:ActiveSupport::HashWithIndifferentAccess 
    first_name: Amanda 
    last_name: Ross 
    is_owner: '1' 
    email: example@googlemail.com 
commit: Update 
action: update 
controller: users 
id: '20' 

而params [：用户]返回：

{"first_name"=>"Amanda", "last_name"=>"Ross", "is_owner"=>"1", "email"=>"example@googlemail.com"} 

所有这些字段都在attr_accessible中模型，我可以创建一个没有任何问题的用户。

这里的development.log输出（抱歉，这是一个有点乱）....

Started PUT "https://stackoverflow.com/users/20" for 127.0.0.1 at 2012-04-17 10:39:29 +0100 
Processing by UsersController#update as HTML 
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"9T4ihVI0p8j7pZEFxof3Bfahi2a+o3BPmtXJDnfHT4o=", "user"=> {"first_name"=>"Amanda", "last_name"=>"Ross", "is_owner"=>"1", "email"=>"example@googlemail.com"},  "commit"=>"Update", "id"=>"20"} 
    [1m[36mUser Load (1.0ms)[0m [1mSELECT "users".* FROM "users" WHERE "users"."id" = 20 LIMIT 1[0m 
>>>>>>>>>>>> 
{"first_name"=>"Amanda", "last_name"=>"Ross", "is_owner"=>"1", "email"=>"example@googlemail.com"} 
    [1m[35m (0.0ms)[0m begin transaction 
    [1m[36mUser Exists (0.0ms)[0m [1mSELECT 1 FROM "users" WHERE (LOWER("users"."email") =  LOWER('example@googlemail.com') AND "users"."id" != 20) LIMIT 1[0m 
    [1m[35mUser Exists (0.0ms)[0m SELECT 1 FROM "users" WHERE ("users"."email" = 'example@googlemail.com'  AND "users"."id" != 20) LIMIT 1 
    [1m[36m (0.0ms)[0m [1mrollback transaction[0m 
Rendered users/_form.html.erb (7.0ms) 
Rendered users/edit.html.erb within layouts/application (10.0ms) 
Rendered layouts/_includes.html.erb (30.0ms) 

谁能可能会帮助指出我要去哪里错了吗？

在此先感谢！

Answer 1

在继续写入数据库之前，#update_attributes和#save都将首先检查您的模型实例是否为#valid?。如果您的模型实例不是#valid?，那么这些方法将返回false。要查看模型实例出了什么问题，请查看模型的#errors。

Rails.logger.info(@user.errors.messages.inspect) 

或者嵌入在你的方法，

def update 
    @user = current_user 
    if @user.update_attributes(params[:user]) 
    redirect_to profile_path, :notice => "Successfully updated profile." 
    else 
    # print the errors to the development log 
    Rails.logger.info(@user.errors.messages.inspect) 
    render :action => 'edit' 
    end 
end 

Answer 2

您也可以通过调用update_attributes!代替，这引起了异常，而不是刚刚返回false更新属性时获得更好的反省。