EF 4.3迁移 - 如何生成降级脚本？ [英] EF 4.3 Migration - how to produce a downgrade script?

问题描述

我有一个问题，我无法在网路上找到答案。

I have an issue which I could not find answer for across the web.

我正在使用CodeFirst EF 4.3.1使用MsSQL进行迁移。

I am using CodeFirst EF 4.3.1 Migrations with MsSQL.

我已经添加了几个迁移，现在我要生成两个迁移之间的升级/降级脚本。

I have added several migrations and now I want to produce a script for upgrade/downgrade between two migrations.

对于升级我运行以下命令成功重现升级脚本：

For upgrade I run the following command which successfully reproduces an upgrade script:

PM> Update-Database -Script -SourceMigration:"201205161144187_AddPostAbstract" -TargetMigration:"201205161203310_BlogLimitsAndTableRename"

但是，我运行以下命令失败，出现以下错误：

However, for downgrade I run the following command which fails with the following error:

PM> Update-Database -Script -SourceMigration:"201205161203310_BlogLimitsAndTableRename" -TargetMigration:"201205161144187_AddPostAbstract"
Scripting the downgrade between two specified migrations is not supported.

任何想法如何生成降级脚本？

Any ideas how can I generate a downgrade script?

谢谢。

推荐答案

看起来像迁移API希望你只想从最后一个版本进行降级。

It looks like migration API expects that you want to do downgrade only from "last version".

如果 BlogLimitsAndTableRename 是您最近的迁移（最后一次应用），您可以简单地运行：

If BlogLimitsAndTableRename is your most recent migration (the last applied) you can simply run:

Update-Database -Script -TargetMigration:"201205161144187_AddPostAbstract"

如果不是您的最后一次迁移，您需要首先将开发数据库还原到其中：

If it is not your last migration you need to revert your development database to it first:

Update-Database -TargetMigration:"201205161203310_BlogLimitsAndTableRename"

现在你应该可以使用第一个命令得到一个脚本。

and now you should be able to use the first command to get a script.

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