如何在带有 EF Core 的 ASP.NET Core 中取消应用迁移

Question

When I run PM> Remove-Migration -context BloggingContext in VS2015 with an ASP.NET Core project using EF Core I get the following error:

System.InvalidOperationException: The migration '20160703192724_MyFirstMigration' has already been applied to the database. Unapply it and try again. If the migration has been applied to other databases, consider reverting its changes using a new migration.    at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.RemoveMigration(String projectDir, String rootNamespace, Boolean force) 
    at Microsoft.EntityFrameworkCore.Design.MigrationsOperations.RemoveMigration(String contextType, Boolean force) 
    at Microsoft.EntityFrameworkCore.Tools.Cli.MigrationsRemoveCommand.<>c__DisplayClass0_0.<Configure>b__0() 
    at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args) 
    at Microsoft.EntityFrameworkCore.Tools.Cli.Program.Main(String[] args) 
 The migration '20160703192724_MyFirstMigration' has already been applied to the database. Unapply it and try again. If the migration has been applied to other databases, consider reverting its changes using a new migration.

How can I unapply it? I'm using latest release of ASP.NET Core 1.0, EF Core, and VS2015 Update 3.

Answer 1

Use:

CLI

> dotnet ef database update <previous-migration-name>

Package Manager Console

PM> Update-Database <previous-migration-name>

Example:

PM> Update-Database MyInitialMigration

Then try to remove last migration.

Removing migration without database update doesn't work because you applied changes to database.

If using PMC, Try: PM> update-database 0 This will wipe the database and allow you to remove the Migration Snapshot on your Solution

Answer 2

To completely remove all migrations and start all over again, do the following:

dotnet ef database update 0
dotnet ef migrations remove

Answer 3

To unapply a specific migration(s) :

dotnet ef database update LastGoodMigrationName
or
PM> Update-Database -Migration LastGoodMigrationName

To unapply all migrations :

dotnet ef database update 0
or
PM> Update-Database -Migration 0

To remove last migration:

dotnet ef migrations remove
or
PM> Remove-Migration

To remove all migrations:

just remove Migrations folder.

To remove last few migrations (not all):

There is no a command to remove a bunch of migrations and we can't just remove these few migrations and their *.designer.cs files since we need to keep the snapshot file in the consistent state. We need to remove migrations one by one (see To remove last migration above).

To unapply and remove last migration:

dotnet ef migrations remove --force
or
PM> Remove-Migration -Force

Answer 4

To revert the last applied migration you should (package manager console commands):

1. Revert migration from database: PM> Update-Database <prior-migration-name>
2. Remove migration file from project (or it will be reapplied again on next step)
3. Update model snapshot: PM> Remove-Migration

UPD : The second step seems to be not required in latest versions of Visual Studio (2017).

Answer 5

You can still use the Update-Database command.

Update-Database -Migration <migration name> -Context <context name>

However, judging by the name of your migration i'm assuming it's the first migration so that command may not work. You should be able to delete the entry from the __MigrationHistory table in your database and then run the Remove-Migration command again. You could also delete the migration file and just start again.

Answer 6

You should delete migration '20160703192724_MyFirstMigration' record from '_EFMigrationsHistory' table.

otherwise below command will remove migration and delete migrations folder:

PMC Command:

   > remove-migration -force

CLI Command:

   > dotnet ef migrations remove -f

Link About CLI Commands

Link About PMC Commands

Answer 7

Simply you can target a Migration by value

 Update-Database -Migration:0

Then go ahead and remove it

 Remove-Migration

NOTE this is for when you want to clear database.

Answer 8

In Package Manager Console:

Update-Database Your_Migration_You_Want_To_Revert_To

More options and explanation on how to revert migrations can be seen here

Answer 9

To "unapply" the most (recent?) migration after it has already been applied to the database:

1. Open the SQL Server Object Explorer (View -> "SQL Server Object Explorer")
2. Navigate to the database that is linked to your project by expanding the small triangles to the side.
3. Expand "Tables"
4. Find the table named "dbo._EFMigrationsHistory".
5. Right click on it and select "View Data" to see the table entries in Visual Studio.
6. Delete the row corresponding to your migration that you want to unapply (Say "yes" to the warning, if prompted).
7. Run "dotnet ef migrations remove" again in the command window in the directory that has the project.json file. Alternatively, run "Remove-Migration" command in the package manager console.

Hope this helps and is applicable to any migration in the project... I tested this out only to the most recent migration...

Happy coding!

Answer 10

In general if you are using the Package Manager Console the right way to remove a specific Migration is by referencing the name of the migration

Update-Database -Migration {Name of Migration} -Context {context}

Another way to remove the last migration you have applied according to the docs is by using the command:

dotnet ef migrations remove

This command should be executed from the developer command prompt ( how to open command prompt ) inside your solution directory.

For example if your application is inside name "Application" and is in the folder c:\Projects. Then your path should be:

C:\Projects\Application

Answer 11

To revert all the migrations which are applied to DB simply run:

update-database 0

It should be followed with running Remove-Migration as many times as there are migration files visible in the Migration directory. The command deletes the latest migration and also updates the snapshot.

Answer 12

dotnet ef database update <the-migration-you-want-to-recover>
dotnet ef migrations remove

Don't forget the remove-Call since this will remove the migration files for you and update the Snapshot-file.

Answer 13

I don't understand why we are confusing things up here. So I'll write down a clear explanation, and what you have to notice .

All the commands will be written using dotnet .

This solution is provided for .net Core 3.1, but should be compatible with all other generations as well

Removing migrations:

• Removing a migration deletes the file from your project (which should be clear for everyone)
• Removing a migration can only be done, if the migration is not applied to the database yet
• To remove last created migration: cd to_your_project then dotnet ef migrations remove

Note: Removing a migration works only, if you didn't execute yet dotnet ef database update or called in your c# code Database.Migrate() , in other words, only if the migration is not applied to your database yet.

Unapplying migrations (revert migrations):

• Removes unwanted changes from the database
• Does not delete the migration file from your project, but allows you to remove it after unapplying
• To revert a migration, you can either:
  • Create a new migration dotnet ef migrations add <your_changes> and apply it, which is recommended by microsoft.
  • Or, update your database to a specified migration (which is basically unapplying or reverting the non chosen migrations) with dotnet ef database update <your_migration_name_to_jump_back_to>

Note: if the migration you want to unapply, does not contain a specific column or table, which are already in your database applied and being used, the column or table will be dropped, and your data will be lost.

After reverting the migration, you can remove your unwanted migration

Answer 14

at first run the following command :

PM>update-database -migration:0

and then run this one :

PM>remove_migration

Finish

Answer 15

In order to unapply a migration in EF Core 1.0 use the command:

dotnet ef database update {migration_name}

Use the migration name of the migration until which you would like to preserve your changes. The list of names of the migration can be found using:

dotnet ef migrations list

Answer 16

Removing a Migration

You can remove the last migration if it is not applied to the database. Use the following remove commands to remove the last created migration files and revert the model snapshot.

Package Manager Console

PM> remove-migration

CLI> dotnet ef migrations remove

The above commands will remove the last migration and revert the model snapshot to the previous migration. Please note that if a migration is already applied to the database, then it will throw the following exception.

The migration has already been applied to the database. Revert it and try again. If the migration has been applied to other databases, consider reverting its changes using a new migration.

Reverting a Migration

Suppose you changed your domain class and created the second migration named MySecondMigration using the add-migration command and applied this migration to the database using the Update command. But, for some reason, you want to revert the database to the previous state. In this case, use the update-database command to revert the database to the specified previous migration snapshot.

Package Manager Console

PM> Update-database MyFirstMigration

CLI

dotnet ef database update MyFirstMigration.

The above command will revert the database based on a migration named MyFirstMigration and remove all the changes applied for the second migration named MySecondMigration. This will also remove MySecondMigration entry from the __EFMigrationsHistory table in the database.

Note: This will not remove the migration files related to MySecondMigration. Use the remove commands to remove them from the project.

Answer 17

Because I've been redirected to this question for searching about roll back migration in ef not ef core , I'm adding this answer to the question for everybody who want to know about the same problem in ef . If you're using ef you can use the following command to roll back the migration:

Update-Database [[-Migration] <String>] 
                [-Context <String>]
                [-Project <String>]
                [-StartupProject <String>] 
                [<CommonParameters>] 

Based on question:

Update-Database -Migration <previous-migration-name> -context BloggingContext

Answer 18

As the question itself deals with a first migration this answer is for anyone who is here looking for way to revert their last migration since most answers do not cover the alternate scenarios (For most of us it's not our first migration and we cannot wipe the entire migration history). These commands are for Package Manager Console.

Let's say you have the following migrations in your code:

• 20220110_InitialMigration
• 20200210_GoodMigration
• 20200210_LastGoodMigration
• 20200210_BadMigration
• 20200210_BadMigrationAgain

If you have already applied the migration to the db like in the question

1. Run:

   Update-Database -Migration <Last_Good_Migration_Name>

   Note: The name should be without date prefix. Eg: Update-Database -Migration LastGoodMigration

2. Then to remove the bad migration run:

   Remove-Migration

   Note: Since we have two bad migrations run the Remove Migration command twice.

If you haven't applied the migration to the db

Just run:

Remove-Migration

In our case run the Remove Migration command twice.

Hope this helps someone.

Answer 19

var context = serviceProvider.GetRequiredService<ApplicationDbContext>();
var userManager = serviceProvider.GetRequiredService<UserManager<ApplicationUser>>();
var roleManaget = serviceProvider.GetRequiredService<RoleManager<IdentityRole>>();

await context.Database.EnsureDeletedAsync();

Answer 20

Really? all the top answers here don't work, Here is what did work: In the Package manager console:

Update-Database 0

this reverts all migrations on the database end.(Maybe its not what you want, but if you are like me and all you had anyways was the initial migration, this would work fine)

Next command is:

remove-migration

The command defaults to your last migration so for initial migration it would remove it. by the way you can do Update-Database --help to get more info on commands.

I'm using.Net6 so maybe that is why things were different than what other people wrote here.

Answer 21

1.find table "dbo._EFMigrationsHistory", then delete the migration record that you want to remove. 2. run "remove-migration" in PM(Package Manager Console). Works for me.

Answer 22

You can do it with:

dotnet ef migrations remove

Warning

Take care not to remove any migrations which are already applied to production databases. Not doing so will prevent you from being able to revert it, and may break the assumptions made by subsequent migrations.

Answer 23

in Package Manager Console, just Type Remove-Migration And Press Enter. It automatically removes the migration.

Tools -> Nuget Package Manager -> Package Manager Console