MVC3和code首先迁移 - ＆QUOT;模型靠山'嗒嗒'环境已经改变，因为数据库创建＆QUOT; [英] MVC3 and Code First Migrations - "model backing the 'blah' context has changed since the database was created"
问题描述
我使用实体框架code首先开始了我的项目。当我准备好了我上传我的数据库和code到我的主机提供商。一切工作。
I started off my project by using Entity Framework Code First. When I was ready I uploaded my database and code to my host provider. Everything worked.
我需要一个新的字段添加到我的课之一，我不想失去在数据库中的数据。因此，我尝试以下有关使用code首先迁移一些博客文章。我做了以下内容：
I need to add a new field to one of my classes and I don't want to loose the data in the database. Thus, I tried following some blog posts about using Code First Migrations. I did the following:
- 我支持我的遥控器（生产）数据库中。
- 我重视本地这个数据库
- 我添加的财产，以我的课
- PM>启用的迁移
- PM>添加迁移AddSortOrderToCar
- PM>更新 - 数据库
- 在这一点上我创建的本地数据库的.bak文件，然后使用该文件来恢复到远程之一。
- 最后，我发表了code到远程站点。
当我访问该网站，我得到了以下错误信息：
该模型靠山'blahblah'环境已经改变，因为该数据库已创建。考虑使用code首先迁移到更新数据库。
When I visit the site I get the following error message: The model backing the 'blahblah' context has changed since the database was created. Consider using Code First Migrations to update the database.
我在做什么错了？
推荐答案
从我的经验表明，迁移表不同步（即使你的数据不是），而这一直是数据库架构的一部分，现在（因为4.3我认为 - 在系统表）。
From my experience that suggests that migration table is out of sync (even if your data isn't), and that's been part of the db schema now (since 4.3 I think - under system tables).
有可能有很多的原因和方式，体验错误，但大部分时间...
There could be many reasons and ways to experience that error , but most of the time...
有问题的部分是手动备份/还原整个数据库code一起变化的某种组合 - 我不是，为什么总是完全肯定。
The problematic part is some combination of manually backing/restoring the full database with code changes alongside - I'm not entirely certain as to why always.
在短，即使DB-s为同一迁移表的数据可能不是 - 和散列比较可能会失败（还是满喜欢恢复不够好声音 - 但你必须'两面'）。
In short, even if Db-s are the same migration table data might not be - and hash comparison may fail (still full restore sounds like good enough - but you have 'two sides').
什么对我的作品是用结果更新，数据库-Script
What works for me is to use
Update-Database -Script
这将创建一个迁移差异，结果一个脚本
您可以手动应用为目标服务器上的数据库SQL脚本（你应该得到正确的迁移表行插入等）。
That creates a script with a 'migration difference',
which you can manually apply as an SQL script on the target server database (and you should get the right migration table rows inserted etc.).
如果仍然无法正常工作 - 你仍然可以做两件事情...
If that still doesn't work - you can still do two things...
a）将迁移表（目标 - 在系统表） - 按<一个href=\"http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-automatic-migrations-walkthrough.aspx\">http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-automatic-migrations-walkthrough.aspx在那里评论 - 应该故障回复到previous行为，如果你确信你的数据库-S是相同的 - 它只是要相信你，
a) remove the migration table (target - under system tables) - as per http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-automatic-migrations-walkthrough.aspx comments in there - that should fail back to previous behavior and if you're certain that your Db-s are the same - it's just going to 'trust you',
B）为我所用最后一招 - 让一个更新，数据库-Script 完整的模式（例如，通过初始化一个空的数据库，应强制执行全剧本'），结果
找到 INSERT INTO [__MigrationHistory] 记录结果
只要运行那些，它们插入到数据库中，搜索
并确保你的数据库 - 和code匹配，
b) as a last resort I used - make a Update-Database -Script of the full schema (e.g. by initializing an empty db which should force a 'full script'),
find the INSERT INTO [__MigrationHistory] records,
just run those, insert them into the database,
and make sure that your databases - and code match,
这应使事情同步再次运行。
that should make things run in sync again.
（免责声明：这不是防弹在任何时候都工作，您可能需要尝试给当地的情景几件事情 - 但应该让你同步）
(disclaimer: this is not a bullet proof to work at all times, you may need to try a few things given your local scenarios - but should get you in sync)
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