运行remove_column不能在rails迁移中运行

Question

我有一个非常简单的迁移:

class RemoveAuthorIdFromBooks < ActiveRecord::Migration
  def change
    remove_column :books, :author_id
  end

end

但是我收到以下错误:

Mysql2::Error: Error on rename of './mysite_staging/#sql-3b1_3c78' to './mysite_staging/books' (errno: 150): ALTER TABLE `books` DROP `author_id`

这是表的描述:

+------------------+---------------+------+-----+---------+----------------+
| Field            | Type          | Null | Key | Default | Extra          |
+------------------+---------------+------+-----+---------+----------------+
| id               | int(11)       | NO   | PRI | NULL    | auto_increment |
| author_id        | int(11)       | NO   | MUL | NULL    |                |
| title            | varchar(255)  | NO   |     | NULL    |                |
| teaser           | varchar(500)  | NO   |     | NULL    |                |
| description      | varchar(2000) | YES  |     | NULL    |                |
| cover_image      | varchar(255)  | NO   |     | NULL    |                |
| publication_date | date          | NO   |     | NULL    |                |
| enabled          | tinyint(1)    | NO   |     | 1       |                |
| created_at       | datetime      | NO   |     | NULL    |                |
| updated_at       | datetime      | NO   |     | NULL    |                |
| excerpt          | text          | YES  |     | NULL    |                |
| featured         | tinyint(1)    | YES  |     | NULL    |                |
| site_id          | int(11)       | YES  |     | NULL    |                |
+------------------+---------------+------+-----+---------+----------------+

有线索吗？

Answer 1

如果有人仍然使用Rails 4及更高版本,那么您可以执行以下操作

remove_reference(:books,:author,index:true,foreign_key:true)