Question

简而言之，在本地Postgres实例上删除，创建和运行迁移将为我的应用创建一个工作数据库任意次数，但Heroku的产品上的相同技术总是产生：

heroku run rake db:migrate
Running `rake db:migrate` attached to terminal... up, run.9674
PG::UndefinedTable: ERROR:  relation "mytable" does not exist
LINE 5:                WHERE a.attrelid = '"mytable"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"mytable"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

rake aborted!
PG::UndefinedTable: ERROR:  relation "mytable" does not exist
LINE 5:                WHERE a.attrelid = '"mytable"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"mytable"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

编辑：请参阅问题的底部，了解在迁移过程中访问控制器的线索。

这是在本地工作的：

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

我有

通过执行heroku pg:psql然后\dt确认Heroku的数据库在迁移之前是空白的，以验证是否存在0个表。
在迁移之前尝试了heroku pg:reset DATABASE
确认本地和prod Postgres版本为9.2.4
尝试重命名db/migrate中的“mytable”迁移文件，以获得最早的时间戳，以便先运行

这是一个非常简单的应用程序，所以非常令人沮丧的是，从头开始创建数据库这样的基本操作仍然会失败。有什么想法吗？

“mytable”迁移：

class CreateMytable < ActiveRecord::Migration
  def change
    create_table :mytable do |t|
      t.string :codes
      t.string :name

      t.timestamps
    end
  end
end

可能参与迁移：

class CreateTable2 < ActiveRecord::Migration
  def change
    create_table :table2 do |t|
      t.references :a, index: true
      t.references :b, index: true
      t.string :c
      t.string :d

      t.timestamps
    end
  end
end

编辑：在使用--trace运行db：migrate时发现了一条线索。堆栈跟踪顶部错误显示控制器错误??为什么控制器会参与迁移？

/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:768:in `exec'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:768:in `exec_no_cache'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:138:in `block in exec_query'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:425:in `block in log'
/app/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:420:in `log'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:137:in `exec_query'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:915:in `column_definitions'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/postgresql/schema_statements.rb:174:in `columns'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/schema_cache.rb:114:in `block in prepare_default_proc'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/schema_cache.rb:56:in `yield'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/schema_cache.rb:56:in `columns'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/model_schema.rb:208:in `columns'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/model_schema.rb:242:in `column_defaults'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/locking/optimistic.rb:169:in `column_defaults'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/core.rb:181:in `initialize'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/inheritance.rb:27:in `new'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0/lib/active_record/inheritance.rb:27:in `new'
/app/app/controllers/home_controller.rb:7:in `<class:HomeController>'

相关第7行包含对Mytable.new(...的调用。在db：migrate？

期间，控制器代码如何进入范围？

Answer 1

这在某种程度上是由Rails控制器中的类变量引起的，该控制器引用了＆＃34; mytable＆＃34;类。基本上就是这样：

 class HomeController < ApplicationController
  @@data = {MyTable.new(...

在控制器方法中移动它并使其成为非类变量可以解决问题（我没有确定它是类var变量方面还是位于类def之下的位置）。

我仍然不明白为什么控制器代码是数据库迁移的一个因素。我有兴趣听听这是我做错了什么，还是耙子，铁轨或其他什么的错误。只发生在Heroku制作中，Rails 4.0.0

rails迁移在本地Postgresql上运行但在prod上失败

1 个答案: