Question

我有一些迁移和现有的schema.rb。我确实拥有了包含记录的所需表格，在开发过程中的某个时刻，我意识到我无法重新创建迁移。

现在我遇到了奇怪的情况：

当我删除数据库并重新运行迁移时，不会抛出任何异常，但未列出迁移且未创建表：
```
$ bin/rake db:drop
$ bin/rake db:create
$ bin/rake db:migrate
```
但是，当我运行迁移时，之前包含所有已创建表的schema.rb现在看起来像这样：
```
ActiveRecord::Schema.define(version: 0) do

end
```

此gist包含原始schema.rb以及迁移。

这是我的database.yml：

development:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: dev_db
  pool: 5
  username: root
  password:
  host: localhost

更新：

我可以通过运行bin/rake db:schema:load重新创建我的数据库。但是，只要我再次运行迁移，整个过程就会被恢复，所有迁移都会降级，我最终会再次出现空schema.rb：

$ bin/rails g migration AddBubuToUser bubu:string
      invoke  active_record
      create    db/migrate/20151203104243_add_bubu_to_user.rb

$ bin/rake db:migrate
== 20151203092755 RemoveNameFromUser: reverting ===============================
-- add_column(:users, :name, :string)
   -> 0.0179s
== 20151203092755 RemoveNameFromUser: reverted (0.0215s) ======================

== 20151203092753 AddNameToUser: reverting ====================================
-- remove_column(:users, :last_name, :string)
   -> 0.0188s
-- remove_column(:users, :first_name, :string)
   -> 0.0176s
== 20151203092753 AddNameToUser: reverted (0.0369s) ===========================

== 20151203091637 AddRoleToUsers: reverting ===================================
-- remove_column(:users, :role, :integer)
   -> 0.0253s
== 20151203091637 AddRoleToUsers: reverted (0.0256s) ==========================

== 20151203091630 AddNameToUsers: reverting ===================================
-- remove_column(:users, :name, :string)
   -> 0.0125s
== 20151203091630 AddNameToUsers: reverted (0.0128s) ==========================

== 20151203091627 DeviseCreateUsers: reverting ================================
-- remove_index(:users, {:column=>:reset_password_token})
   -> 0.0214s
-- remove_index(:users, {:column=>:email})
   -> 0.0200s
-- drop_table(:users)
   -> 0.0010s
== 20151203091627 DeviseCreateUsers: reverted (0.0432s) =======================

运行迁移时，清除`schema.rb`并将其设置为版本`0`

0 个答案: