Rails模型数据验证 #

一、验证概述 #

1.1 什么是验证 #

验证确保数据在保存到数据库前符合特定规则，保证数据的完整性和一致性。

1.2 验证时机 #

create
update
save

二、内置验证器 #

2.1 存在性验证 #

ruby

class Article < ApplicationRecord
  validates :title, presence: true
  validates :title, :body, presence: true
end

2.2 唯一性验证 #

ruby

class User < ApplicationRecord
  validates :email, uniqueness: true
  validates :email, uniqueness: { scope: :account_id }
end

2.3 长度验证 #

ruby

class Article < ApplicationRecord
  validates :title, length: { minimum: 5 }
  validates :title, length: { maximum: 100 }
  validates :title, length: { in: 5..100 }
  validates :title, length: { is: 50 }
end

2.4 格式验证 #

ruby

class User < ApplicationRecord
  validates :email, format: { with: /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i }
end

2.5 数值验证 #

ruby

class Product < ApplicationRecord
  validates :price, numericality: { greater_than: 0 }
  validates :quantity, numericality: { only_integer: true }
end

三、自定义验证 #

3.1 自定义验证方法 #

ruby

class Article < ApplicationRecord
  validate :expiration_date_cannot_be_in_the_past
  
  def expiration_date_cannot_be_in_the_past
    if expiration_date.present? && expiration_date < Date.today
      errors.add(:expiration_date, "can't be in the past")
    end
  end
end

四、条件验证 #

4.1 条件执行 #

ruby

class Order < ApplicationRecord
  validates :card_number, presence: true, if: :paid_with_card?
  
  def paid_with_card?
    payment_type == 'card'
  end
end

五、总结 #

5.1 核心要点 #

要点	说明
presence	存在性验证
uniqueness	唯一性验证
length	长度验证
format	格式验证
自定义验证	自定义验证方法

5.2 下一步 #

现在你已经掌握了数据验证，接下来让我们学习查询接口，深入了解Rails的查询方法！