-
```
list 实现一个可排序、可调整列表项位置的列表。
list
是一个双连接链表,每个元素都连接到前一个项目和后一个��
�目。
list
的优势在于增加项目、删除项目、移动项目位置时速度快(��
�需要更新前后的项
目),缺点是无法按照按照严格索引值访问特定列表项目。��
�如要访问排序位置第三
位的项目,只能从第一个项目开始向后查找。幸运的是我们��
�特定项目的ID记录下
来,以…
-
```
versioned 行为插件可以为对象提供版本控制能力。例如 wiki
的文章具备多个版本。
使用 versioned 插件后,可以在数据库中保存对象的多个版本。
生成对象的新版本时,老版本的对象会获得一个新的ID,而最
新的内容则占用现有的
ID。因此,以ID查询对象时,总是会获得最新版本的内容。
versioned 插件提供下列方法:
// 获得当前的版本号
string …
-
Allow specification of XMigra migrations as ActiveRecord::Migration code.
Reversible migrations should store reversion steps in the database for application when/if a new upgrade script that modifies…
-
Quikly. When I have in my model:
``` ruby
accepts_nested_attributes_for :foofoo, :allow_destroy => true, :limit => 2
```
When I do the next I get the error. But it shouldn't show because only one Fo…
-
Up to version 5.3.3 audited could be used as an extension of activerecord without rails. I would suggest to check the version of activerecord with ActiveRecord.gem_version instead of Rails.gem_version…
-
### Steps to reproduce
```ruby
# frozen_string_literal: true
require "bundler/inline"
gemfile(true) do
source "https://rubygems.org"
gem "rails", github: "rails/rails", branch: "…
-
User model
```ruby
class User < ApplicationRecord
has_secure_password
end
```
```ruby
created_user = User.create!(name: "Foo", password: "abc123")
created_user.update!(name: "Bar", password:…
-
UPDATE: Code to reproduce the problem is in comments
I have a Rails project with the following models:
```
account
username
user
address
```
With the following associations:
```
class Account < Ac…
-
I have a use case (a university web site) where I must model supervisor/employee relationships.
These are essentially parent/child relationships, except that anyone can have an arbitrary number o…
-
https://sentry.io/share/issue/0abeb7d376b2479a9ebbdd9f64d04a50/
Two possible solutions to this:
1. Sanitise (scrub) data before they are saved to DB.
2. Set the encoding at DB level (this can b…