ActionView::Template::Error（PG :: UndefinedColumn：ERROR：列“weeknumber”不存在）

Question

我在使用activeRecord在heroku上的PG数据库时遇到问题。我目前有以下代码，它完全正常工作，但偶尔记录不按照我想要的顺序排列。因此，我尝试在数据库上使用.order函数，现在我得到了PG :: UndefinedColumn：ERROR。如果我删除.order函数，则它会再次正常工作。

当出现错误时，模型或数据库中没有任何更改。只是尝试添加.order函数来控制数据库记录的顺序。

另外，在sqlite3数据库的开发环境中也可以正常工作。

以下是正常工作的代码：

1 <table class="table table-striped table-bordered table-condensed table-hover">
2   <tr>
3     <td></td>
4     <% @pool.weeks.each do |week| %>
5       <td class="entry-header">
6         <%= "Week #{week.weekNumber}" %> 
7       </td>
8     <% end %>
9   </tr>

这里是导致它出现问题的更改：

Change line 4 from this:
   4     <% @pool.weeks.each do |week| %>
to this:
   4     <% @pool.weeks.order("weekNumber ASC").each do |week| %>

一旦我添加.order功能，它在Heroku上就会出现以下错误:

app[web.1]: ActionView::Template::Error (PG::UndefinedColumn: ERROR:  column "weeknumber" does not exist
app[web.1]:     2:   <tr>
app[web.1]: LINE 1: ...M "weeks"  WHERE "weeks"."pool_id" = $1  ORDER BY weekNumber...
app[web.1]: : SELECT "weeks".* FROM "weeks"  WHERE "weeks"."pool_id" = $1  ORDER BY weekNumber ASC):
app[web.1]:
app[web.1]:     1: <table class="table table-striped table-bordered table-condensed table-hover">
app[web.1]:     4:     <% @pool.weeks.order("weekNumber ASC").each do |week| %>
app[web.1]:     3:     <td></td>
app[web.1]: LINE 1: ...M "weeks"  WHERE "weeks"."pool_id" = $1  ORDER BY weekNumber...
app[web.1]:     5:       <td class="entry-header">
app[web.1]:   app/views/pools/_show_board.html.erb:4:in   `_app_views_pools__show_board_html_erb___2914673273129495301_70355170381800'
app[web.1]:
app[web.1]:     3:     <td></td>
app[web.1]:   app/views/pools/show.html.erb:28:in `_app_views_pools_show_html_erb__33868809623974782_70355169938300'
app[web.1]:     6:         <%= "Week #{week.weekNumber}" %>
app[web.1]: ActionView::Template::Error (PG::UndefinedColumn: ERROR:  column "weeknumber" does not exist
app[web.1]:
app[web.1]:     7:       </td>
app[web.1]: : SELECT "weeks".* FROM "weeks"  WHERE "weeks"."pool_id" = $1  ORDER BY weekNumber ASC):
app[web.1]:   app/views/pools/_show_board.html.erb:4:in `_app_views_pools__show_board_html_erb___2914673273129495301_70355170381800'
app[web.1]:     2:   <tr>
app[web.1]:     5:       <td class="entry-header">
app[web.1]:   app/views/pools/show.html.erb:28:in `_app_views_pools_show_html_erb__33868809623974782_70355169938300'
app[web.1]:     7:       </td>
app[web.1]:
app[web.1]:
app[web.1]:                                                              ^
app[web.1]:     1: <table class="table table-striped table-bordered table-condensed table-hover">
app[web.1]:     4:     <% @pool.weeks.order("weekNumber ASC").each do |week| %>
app[web.1]:     6:         <%= "Week #{week.weekNumber}" %>
app[web.1]:
heroku[router]: at=info method=GET path=/pools/1 host=fb-pools.herokuapp.com fwd="76.250.116.65" dyno=web.1 connect=5ms service=142ms status=500 bytes=643
heroku[web.1]: Stopping all processes with SIGTERM

数据库中没有任何更改。唯一的变化是添加了.order函数。我猜测我的迁移中缺少了某些内容，但不确定是什么。

这是与周模型相关联的迁移文件：

class CreateWeeks < ActiveRecord::Migration
  def change
    create_table :weeks do |t|
      t.integer :state
      t.integer :pool_id

      t.timestamps
    end
  end
end

class AddWeekNumberToWeeks < ActiveRecord::Migration
  def change
    add_column :weeks, :weekNumber, :integer
  end
end

这里是池和周模型：

class Pool < ActiveRecord::Base

  POOL_TYPES = { PickEm: 0, PickEmSpread: 1, Survivor: 2, SUP: 3 }

  has_many :users, through: :pool_memberships, dependent: :destroy
  has_many :pool_memberships, dependent: :destroy
  has_many :weeks, dependent: :destroy
  has_many :entries, dependent: :destroy

  # Make sure protected fields aren't updated after a week has been created on the pool
  validate :checkUpdateFields, on: :update

  attr_accessor :password

  validates :name,     presence:   true,
                       length:      { :maximum => 30 },
                       uniqueness:  { :case_sensitive => false }
  validates :poolType, inclusion:   { in: 0..3 }
  validates :allowMulti, inclusion: { in: [true, false] }
  validates :isPublic, inclusion:   { in: [true, false] }

  ...   

end

class Week < ActiveRecord::Base

  STATES = { Pend: 0, Open: 1, Closed: 2, Final: 3 }

  belongs_to :pool
  has_many   :games, dependent: :destroy
  has_many   :picks, dependent: :destroy

  accepts_nested_attributes_for :games

  ...

end

- Robert Reynolds

---

可能是重复的问题：Rails报告找不到已经存在的列 - Zach Kemp

@ZachKemp：这正是问题所在，他们必须像 .order('"weekNumber" ASC') 这样说出那些列名。或者将该列创建为 :week_number，这样就不必担心了。 - mu is too short

看起来我遇到了同样的问题。然而，解决这个问题的方法是重新制作整个数据库并删除大小写混合的表项。不幸的是，由于应用程序正在运行，我现在无法重做我的表格。那么，我该如何让order()函数处理这个大小写混合的问题呢？ - Robert Reynolds

Answer 1

您的列名为weekNumber，但ActiveRecord不区分大小写，因此正在查找名为weeknumber的列。

将您的列名更改为week_number并更新您的order为week_number即可解决问题。

- Betjamin Richards

Answer 2

双引号分隔驼峰命名。

从这个：

<% @pool.weeks.order("weekNumber ASC").each do |week| %>

TO THIS

<% @pool.weeks.order("\"weekNumber\" ASC").each do |week| %>

- l3x