Rails rake aborted！t.sqlite3已经存在

Question

我重新安装了回形针gem，但在尝试运行迁移时遇到错误。 （注意：我只从文本编辑器中删除了原始的迁移文件）。具体来说，当我跑：

$ rake db:migrate

我遇到了：

rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:

SQLite3::SQLException: duplicate column name: image_file_name: ALTER TABLE "pins" ADD "image_file_name" varchar
c:/Users/Jaye/Desktop/inspireboard/db/migrate/20160929074428_add_attachment_image_to_pins.rb:4:in `block in up'
c:/Users/Jaye/Desktop/inspireboard/db/migrate/20160929074428_add_attachment_image_to_pins.rb:3:in `up'
c:in `migrate'
ActiveRecord::StatementInvalid: SQLite3::SQLException: duplicate column name: image_file_name: ALTER TABLE "pins" ADD "image_file_name" varchar
c:/Users/Jaye/Desktop/inspireboard/db/migrate/20160929074428_add_attachment_image_to_pins.rb:4:in `block in up'
c:/Users/Jaye/Desktop/inspireboard/db/migrate/20160929074428_add_attachment_image_to_pins.rb:3:in `up'
c:in `migrate'
SQLite3::SQLException: duplicate column name: image_file_name
c:/Users/Jaye/Desktop/inspireboard/db/migrate/20160929074428_add_attachment_image_to_pins.rb:4:in `block in up'
c:/Users/Jaye/Desktop/inspireboard/db/migrate/20160929074428_add_attachment_image_to_pins.rb:3:in `up'
c:in `migrate'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

看到上述内容后，我尝试运行rake db:drop，但遇到了：

Permission denied @ unlink_internal

有人可以建议如何解决这个问题吗？ （注意：我使用的是Windows 8，rails 4.2.5.1，paperclip 4.3.7） 欣赏很多！

Answer 1

删除development.sqlite3文件并重新运行db：migrate解决了问题！

Answer 2

检查是否关闭Rails服务器以运行rake db：drop。我遇到了同样的问题，然后你重新安装了papperclip。我希望我帮助过。