Rails:#update_attribute 与 #update_attributes [英] Rails: #update_attribute vs #update_attributes

问题描述

obj.update_attribute(:only_one_field, 'Some Value')obj.update_attributes(field1: 'value', field2: 'value2', field3: 'value3')

这两种方法都将更新一个对象，而无需显式告诉 ActiveRecord 进行更新.

Rails API 说:

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更新属性

更新单个属性并保存记录，而无需通过正常的验证程序.这对于现有记录上的布尔标志特别有用.混合验证模块时，Base 中的常规 update_attribute 方法将替换为 this，默认情况下.

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更新属性

从传入的Hash中更新所有属性并保存记录.如果对象无效，则保存失败并返回false.

因此，如果我不想验证对象，我应该使用 #update_attribute.如果我在 #before_save 上有这个更新，它会出现 stackoverflow 吗?

我的问题是 #update_attribute 是否也绕过了 before save 或只是验证.

此外，将哈希传递给 #update_attributes 的正确语法是什么...请查看顶部的示例.

解决方案

请参考 update_attribute.单击显示源后，您将获得以下代码

 # 文件 vendor/rails/activerecord/lib/active_record/base.rb, line 26142614:def update_attribute(名称，值)2615:发送(name.to_s + '='，值)2616:保存(假)2617:结束

现在参考 update_attributes 和看看你得到的代码

 # 文件 vendor/rails/activerecord/lib/active_record/base.rb, line 26212621:def update_attributes(属性)2622:self.attributes = 属性2623:保存2624:结束

两者的区别在于update_attribute 使用 save(false) 而 update_attributes 使用 save 或者你可以说save(true).

抱歉描述太长，但我想说的很重要.save(perform_validation = true)，如果perform_validation 是假的，它绕过(skips 将是正确的词)所有 验证 与 save 相关联.

第二个问题

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此外，将哈希传递给 update_attributes 的正确语法是什么...请查看顶部的示例.

你的例子是正确的.

Object.update_attributes(:field1 => "value", :field2 => "value2", :field3 => "value3")

或

Object.update_attributes :field1 =>"值", :field2 =>"value2", :field3 =>值3"

或者如果您获得所有字段数据 &散列中的名称说 params[:user] 在这里只使用

Object.update_attributes(params[:user])

obj.update_attribute(:only_one_field, 'Some Value')
obj.update_attributes(field1: 'value', field2: 'value2', field3: 'value3')

Both of these will update an object without having to explicitly tell ActiveRecord to update.

Rails API says:

update_attribute

Updates a single attribute and saves the record without going through the normal validation procedure. This is especially useful for boolean flags on existing records. The regular update_attribute method in Base is replaced with this when the validations module is mixed in, which it is by default.

update_attributes

Updates all the attributes from the passed-in Hash and saves the record. If the object is invalid, the saving will fail and false will be returned.

So if I don't want to have the object validated I should use #update_attribute. What if I have this update on a #before_save, will it stackoverflow?

My question is does #update_attribute also bypass the before save or just the validation.

Also, what is the correct syntax to pass a hash to #update_attributes ... check out my example at the top.

解决方案

Please refer to update_attribute. On clicking show source you will get following code

      # File vendor/rails/activerecord/lib/active_record/base.rb, line 2614
2614:       def update_attribute(name, value)
2615:         send(name.to_s + '=', value)
2616:         save(false)
2617:       end

and now refer update_attributes and look at its code you get

      # File vendor/rails/activerecord/lib/active_record/base.rb, line 2621
2621:       def update_attributes(attributes)
2622:         self.attributes = attributes
2623:         save
2624:       end

the difference between two is update_attribute uses save(false) whereas update_attributes uses save or you can say save(true).

Sorry for the long description but what I want to say is important. save(perform_validation = true), if perform_validation is false it bypasses (skips will be the proper word) all the validations associated with save.

For second question

Also, what is the correct syntax to pass a hash to update_attributes... check out my example at the top.

Your example is correct.

Object.update_attributes(:field1 => "value", :field2 => "value2", :field3 => "value3")

or

Object.update_attributes :field1 => "value", :field2 => "value2", :field3 => "value3"

or if you get all fields data & name in a hash say params[:user] here use just

Object.update_attributes(params[:user])

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