EF代码优先-无法检查模型兼容性，因为数据库不包含模型元数据 [英] EF code first - Model compatibility cannot be checked because the database does not contain model metadata

问题描述

我已启用自动迁移.然后，我删除了整个数据库.接下来，我从命令控制台执行了Update-database，它重新创建了我的数据库.然后，我启动我的应用程序仅看到此错误:

I have enabled automatic migrations. Then, I deleted my whole db. Next, i executed Update-database from command console, and it recreated my db. Then, I started my application only to see this error:

无法检查模型兼容性，因为数据库没有 包含模型元数据.只能检查型号兼容性 使用代码优先"或代码优先"迁移创建的数据库.

Model compatibility cannot be checked because the database does not contain model metadata. Model compatibility can only be checked for databases created using Code First or Code First Migrations.

那元数据到底是什么，我该如何指向它呢?

So what exactly is that metadata, and how can I point entity framework to it?

PS.我的数据库包含名为MigrationsHistory的表.

PS. My database contains table named MigrationsHistory.

推荐答案

这是我前一段时间写的解决此问题的可能方法的详细说明...
(不完全是您所经历的，因此本身并不是重复的，而是要考虑不同的情况)

Here is a detailed description of the possible ways to resolve this which I wrote a while ago...
(not exactly what you're experiencing, hence not a duplicate per se, but with different scenarios in mind)

https://stackoverflow.com/a/10255051/417747

总结...

对我有用的是使用Update-Database -Script

What works for me is to use Update-Database -Script

这会创建一个带有迁移差异"的脚本，您可以 在目标服务器数据库上手动将其作为SQL脚本手动应用 应该插入正确的迁移表行等.

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.).

如果那仍然不起作用-您仍然可以做两件事...

If that still doesn't work - you can still do two things...

a)删除迁移表(目标-在系统表下)-按照 http: //blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-automatic-migrations-walkthrough.aspx 那里的评论-应该会退回到以前的行为，如果 您确定您的Db-s相同-这只是为了'信任 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)作为我最后使用的方法-创建一个Update-Database -Script 完整模式(例如，通过初始化一个空的db来强制执行 '完整脚本')，找到INSERT INTO [__MigrationHistory]记录， 只需运行它们，将它们插入数据库，并确保您的 数据库-和代码匹配，

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,

应该使事情再次同步运行.

that should make things run in sync again.

如果有帮助

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