📅 最后修改于: 2021-01-12 02:52:34 🧑 作者: Mango
Rails验证为每个Active Record模型类定义有效状态。它们用于确保仅将有效的详细信息输入到数据库中。 Rails使向模型类添加验证变得容易，并且还允许您创建自己的验证方法。使用内置的验证DSL，您可以执行多种验证。
如果Active Record模型类的验证失败，则将其视为错误。每个Active Record模型类都维护一个错误集合，当发生验证错误时，这些错误集合会向用户显示适当的错误信息。
| Method | Description |
|---|---|
| validates_acceptance_of | This validation is done by the user to accept a terms of service agreement by checking in a check box |
| validates_associated | Validates whether associated objects are all valid themselves. Work with any kind of association. |
| validates_confirmation_of | It validates whether a user has entered matching information like password or email in second entry field. |
| validates_each | Validates each attribute against a block. |
| validates_exclusion_of | Validates that an attribute is not in a particular enumerable object. |
| validates_format_of | Validates value of an attribute using a regular expression to insure it is of correct format. |
| validates_inclusion_of | Validates whether value of an attribute is available in a particular enumerable object. |
| validates_length_of | Validates that length of an attribute matches length restrictions specified. |
| validates_numericality_of | Validates whether an attribute is numeric. |
| validates_presence_of | Validates that attribute is not blank. |
| validates_size_of | This is an alias for validates_length_of |
| validates_uniqueness_of | Validates that an attribute is unique in the database. |
以下Rails方法将跳过验证，并将对象保存到数据库中，而不管其有效性如何。应谨慎使用它们。
保存Active Record对象之前，Rails会进行验证。如果产生任何错误，则不保存对象。
有效吗?触发您的验证，如果未发现错误，则返回true，否则返回false。
例：
class Person < ApplicationRecord
??validates :name, presence: true
end
?
Person.create(name: "John Cena").valid? # => true
Person.create(name: nil).valid? # => false
无效吗?是有效的反向吗?它触发您的验证，如果无效则返回true，否则返回false。