Question

将新的列events_count添加到表users后，我收到此错误：

SQLite3::SQLException: no such column: events_count: UPDATE "users" SET "events_count" = COALESCE("events_count", 0) + 1 WHERE "users"."id" = 2

这是带有错误行的提取源：

@event.user_id = current_user.id
respond_to do |format|
  **if @event.save**
    format.html { redirect_to @event, notice: 'Event was successfully created.' }
    format.json { render :show, status: :created, location: @event }
  else

这是我的用户表：

create_table "users", force: true do |t|
  .
  .
  .
  .
  t.integer  "events_count",           default: 0
end

这是来自users_path排名的html：

<tr>
  <% User.all.each  do |user| %> 
    <td> <%= user.name %></td>
    <td> <%= user.events_count %></br></td> 
  <% end %>
</tr>

这是事件模型：

class Event < ActiveRecord::Base
  acts_as_commontable
  mount_uploader :picture, PictureUploader
  acts_as_votable
  belongs_to :user, dependent: :destroy,counter_cache: true
end

任何人都知道可能出现的问题？

编辑：

这是迁移文件：

class AddEventsCountToUsers < ActiveRecord::Migration
  def change
    add_column :users, :events_count, :integer, :default => 0
  end
end

这是事件控制器：

# POST /events
  # POST /events.json
  def create
    @event = Event.new(event_params)
    @event.user_id = current_user.id 
    respond_to do |format|
      if @event.save
        format.html { redirect_to @event, notice: 'Event was successfully created.' }
        format.json { render :show, status: :created, location: @event }
      else
        format.html { render :new }
        format.json { render json: @event.errors, status: :unprocessable_entity }
      end
    end
  end
# Never trust parameters from the scary internet, only allow the white list through.
    def event_params
      params.require(:event).permit(:title, :description, :picture, :start_date, :start_time, :end_time, :location, :user_id, :city)
    end
end

Answer 1

将用户表编辑为：

create_table "users", force: true do |t|
.
.
.
.
 t.integer  :events_count, default: 0
end

运行以下命令： -

rake db:drop
rake db:create
rake db:migrate

注意： - 它将删除数据库中的所有数据

Answer 2

似乎您刚刚将event_counts而非events_count添加到已存在的create_users.rb迁移文件中。

您必须执行查询，为额外列events_count

生成迁移文件

rails g migration AddEventsCountToUsers events_count:integer

在那之后执行rake db：migrate

或

执行rake db:rollback，在create_users.rb迁移文件中添加该列并执行rake db:migrate

如评论中所述，请尝试运行rake db:migrate:up VERSION=20140511122817

EventsController #create中的ActiveRecord :: StatementInvalid

2 个答案: