铁轨毁坏脚手架留下后桌

我使用命令创建了一个新的脚手架:

rails generate scaffold level

但后来我用命令摧毁了它

rails destroy scaffold level

然后再使用该命令将其添加回来

rails generate scaffold level question:string answer:string prev_q:integer next_q:integer

但是现在当我尝试rake db:migrate时,我收到以下错误

 SQLite3::SQLException: table "levels" already exists: CREATE TABLE "levels" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "question" varchar(255), "answer" varchar(255), "prev_q" integer, "next_q" integer, "created_at" datetime NOT NULL, "updated_at" datetime NOT NULL)

我的migrate/create_level.rb是

class CreateLevels < ActiveRecord::Migration
def change
  create_table :levels do |t|
  t.string :question
  t.string :answer
  t.integer :prev_q
  t.integer :next_q

  t.timestamps
  end
 end
end

但我的schema.rb是:

  create_table "levels", :force => true do |t|
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
  end

我想知道如何更新架构中的级别表.另外我想知道为什么在我销毁脚手架时表不会被删除.我是否需要运行另一个命令才能执行此操作？