ActiveRecord(一)

ActiveRecord(一)

命名和模式约定

命名约定

模式约定

不使用约定

指定表名

self.table_name

指定主键

self.primary_key

基本操作

创建

User.create(:name => 'xiaowang', :email => 'xiaowang@gmail.com')

@user = User.new(:name => 'xiaowang', :email => 'xiaowang@gmail.com')
@user.save

读取

User.all

User.find  #（主键）

User.find_by(:name => 'xiaowang') #第一个符合条件的

更新

@user.update(:name => 'xiaowang', :email => 'xiaowang@gmail.com')

User.update_all(:name => 'nima')

删除

删除一个数据

@user.destroy

删除表中所有数据

User.destroy_all

数据迁移

迁移

rake db:migrate

回滚

rake db:rollback

rake db:rollback STEP=2

单独创建迁移

Creatxxx

rails g migration CreateWallets

AddxxxToyyy

rails g migration AddLocationToUser location:string

RemovexxxFromyyy

rails g migration RemoveLocationFromUser location:string

change方法

table

create_table

rename_table

drop_table

join_table

create_join_table

drop_join_table

column

add_column

rename_column

remove_column

index

add_index

rename_index

remove_index

reference

add_reference

remove_reference

timestamps

add_timestamps

remove_timestamps

up和down方法

revert方法

require_relative "20161202100202_create_uesrs"

class RevertCreateUsers < ActiveRecord::Migration
  def change
    revert CreateUsers
  end
end

种子数据

db/seed.rb

15.times do |n|
  User.create(:name => 'male_user_#{n}', :phone_number => '13012312311', :gender => 'male' )
  User.create(:name => 'female_user_#{n}', :phone_number => '13012312311', :gender => 'female' )

end

搭建数据库

rake db:setup

填充种子数据

rake db:seed

重建数据库

rake db:reset

设置环境

RAILS_ENV=test

导出数据库

rake db:schema:load

数据验证

跳过数据验证

@user.save(validate:false)

是否合法

valid？

@user.valid？

invalid？

@user.invalid？

错误信息

@user.errors.messages

@user.errors[:name]

presence

不为空

class User < ApplicationRecord

  validates :name, presence: true

end

absence

为空

validates :name, absence: true

length

长度

• minimum
• maximum
• in
• is

  validates :name, length: {maximum: 3}
  validates :name, length: {in: 3..20}
  validates :name, length: {is: 6}

confirmation

确认

validates :password, confirmation: true

inclusion/exclusion

范围

validates :province, inclusion: {in: ['北京', '上海']}
validates :age, exclusion: {in: 0..18}

format

格式

validates :phone_number, format: {with: /1[0-9]{10}\z/ }

uniqueness

唯一

validates :name, uniqueness: true

不区分大小写

validates :name, uniqueness: {case_sensitive: false}

常用验证选项

• allow_nil
• allow_blank
• message
• on

  validates :password, confirmation: true
  validates :password, :password_confirmation, presence: {on: :create, message: '密码和确认密码不能为空'}
  validates :password, length: {minimum: 6}
  
  
   validates :name, uniqueness: {allow_nil: true}

条件验证

指定symbol

validates :name, uniqueness: true, :if => :test?
 
 def test?
   false
 end

指定字符串

validates :phone_number, uniqueness: true, :if => 'name.nil'

指定proc

validates :phone_number, uniqueness: true, :if => Proc.new {name.nil?}

with_options if: :test? do
  validates :name, uniqueness: true
  validates :name, uniqueness: true

end

def test?
  (1+1 == 2)
end

联合条件

with_options if: :test?, unless: :test2? do
  validates :name, uniqueness: true
  validates :name, uniqueness: true

end

def test?
  (1+1 == 2)
end

  def test2?
    (1+1 == 2)
  end

自定义验证方法

• validates_with
• validates_each

  class MyValidator < ActiveModel::Validator
  
    def validate(record)
      if record.name.nil?
        record.errors[:name] << '用户名不能为空'
      end
      if record.phone_number.nil?
        record.errors[:phone_number] << '手机号码不能为空'
      end
  
    end
  end
  
  
  class User < ApplicationRecord
  
    validates_with MyValidator
  
  end

class User < ApplicationRecord

  validate :my_validator

  def my_validator
    if name.nil?
      errors[:name] << '用户名不能为空'
    end
  end

end

验证错误

• errors
• errors[:attribute]
• errors.add
• errors.size