重置实体框架迁移

小咪咪 2022-11-27 03:09 86阅读 0赞

本文翻译自：[Reset Entity-Framework Migrations][]

*I've mucked up my migrations, I used `IgnoreChanges` on the initial migration, but now I want to delete all my migrations and start with an initial migration with all of the logic.* **我已经对迁移进行了处理，在初始迁移中使用了`IgnoreChanges` ，但是现在我想删除所有迁移，并从所有逻辑开始进行初始迁移。**

*When I delete the migrations in the folder and try and `Add-Migration` it doesn't generate a full file (it's empty - because I haven't made any changes since my last, but now deleted, migration).* **当我删除文件夹中的迁移并尝试执行“ `Add-Migration`它不会生成完整的文件（该文件为空-因为自上次迁移以来，我没有进行任何更改，但是现在删除了该迁移）。**

*Is there any Disable-Migrations command, so I can rerun `Enable-Migrations` ?* **是否有任何*Disable-Migrations*命令，所以我可以重新运行`Enable-Migrations` ？**

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### \#1楼 ###

参考：[https://stackoom.com/question/N0lb/重置实体框架迁移][https_stackoom.com_question_N0lb]

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### \#2楼 ###

*You need to :* **你需要 ：**

1.  *Delete the state: Delete the migrations folder in your project;* **删除状态：删除项目中的migrations文件夹；** *And* **和**
2.  *Delete the `__MigrationHistory` table in your database (may be under system tables);* **删除数据库中的`__MigrationHistory`表（可能在系统表下）；** *Then* **然后**
3.  *Run the following command in the Package Manager Console:* **在程序包管理器控制台中运行以下命令：**
    
        Enable-Migrations -EnableAutomaticMigrations -Force
    
    *Use with or without `-EnableAutomaticMigrations`* **与`-EnableAutomaticMigrations`一起使用或不`-EnableAutomaticMigrations`**
4.  *And finally, you can run:* **最后，您可以运行：**
    
        Add-Migration Initial

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### \#3楼 ###

*My problem turned out to be that I manually removed the Migrations folder.* **我的问题原来是我手动删除了Migrations文件夹。** *I did that because I wanted to back up the contents, so I simply dragged the folder out of the project.* **我这样做是因为我想备份内容，所以我只是将文件夹拖出了项目。** *I later fixed the problem by putting it back in (after making a backup copy), then removing the Migrations folder by right-clicking it in Solutions Explorer and choosing Delete from the popup menu.* **稍后，我通过将其放回（制作完备份副本后），然后通过在“解决方案资源管理器”中右键单击它并从弹出菜单中选择“删除”来删除“迁移”文件夹来解决该问题。**

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### \#4楼 ###

*The Issue: You have mucked up your migrations and you would like to reset it without deleting your existing tables.* **问题：您已经对迁移进行了重新设计，并且希望在不删除现有表的情况下进行重置。**

*The Problem: You can't reset migrations with existing tables in the database as EF wants to create the tables from scratch.* **问题：由于EF希望从头开始创建表，因此无法使用数据库中的现有表重置迁移。**

*What to do:* **该怎么办：**

1.  *Delete existing migrations from Migrations\_History table.* **从Migrations\_History表中删除现有迁移。**
2.  *Delete existing migrations from the Migrations Folder.* **从“迁移”文件夹中删除现有的迁移。**
3.  *Run add-migration Reset.* **运行添加迁移重置。** *This will create a migration in your Migration folder that includes creating the tables (but it will not run it so it will not error out.)* **这将在包含创建表的“迁移”文件夹中创建一个迁移（但是不会运行它，因此不会出错）。**
4.  *You now need to create the initial row in the MigrationHistory table so EF has a snapshot of the current state.* **现在，您需要在MigrationHistory表中创建初始行，以便EF拥有当前状态的快照。** *EF will do this if you apply a migration.* **如果您应用迁移，EF将执行此操作。** *However, you can't apply the migration that you just made as the tables already exist in your database.* **但是，由于表已经存在于数据库中，因此无法应用刚刚进行的迁移。** *So go into the Migration and comment out all the code inside the "Up" method.* **因此，进入“迁移”并注释掉“ Up”方法中的所有代码。**
5.  *Now run update-database.* **现在运行update-database。** *It will apply the Migration (while not actually changing the database) and create a snapshot row in MigrationHistory.* **它将应用迁移（而不实际更改数据库）并在MigrationHistory中创建快照行。**

*You have now reset your migrations and may continue with normal migrations.* **现在，您已重置了迁移，并可以继续进行正常迁移。**

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### \#5楼 ###

*How about* **怎么样**

Update-Database –TargetMigration: $InitialDatabase

*in Package Manager Console?* **在Package Manager控制台中？** *It should reset all updates to its very early state.* **它应该将所有更新重置为非常早的状态。**

*Reference link: [Code First Migrations - Migrating to a Specific Version (Including Downgrade)][Code First Migrations - Migrating to a Specific Version _Including Downgrade]* **参考链接： [代码优先迁移-迁移到特定版本（包括降级）][Code First Migrations - Migrating to a Specific Version _Including Downgrade]**

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### \#6楼 ###

*In EntityFramework 6 please try:* **在EntityFramework 6中，请尝试：**

Add-Migration Initial

*in order to update the initial migration file.* **为了更新初始迁移文件。**

[Reset Entity-Framework Migrations]: https://oldbug.net/q/N0lb/Reset-Entity-Framework-Migrations
[https_stackoom.com_question_N0lb]: https://stackoom.com/question/N0lb/%E9%87%8D%E7%BD%AE%E5%AE%9E%E4%BD%93%E6%A1%86%E6%9E%B6%E8%BF%81%E7%A7%BB
[Code First Migrations - Migrating to a Specific Version _Including Downgrade]: http://msdn.microsoft.com/en-us/data/jj591621#specific